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1

MRI nerve root enhancement in Krabbe disease.  

PubMed

Krabbe disease is characterized by abnormal breakdown and turnover of myelin, leading to extensive demyelination in both the peripheral and central nervous systems. A 7-month-old infant with early-onset Krabbe disease had deceptively normal head images, but spinal MRI demonstrated abnormal gadolinium enhancement of the lumbosacral sacral nerve roots and cauda equina such as that seen in Guillain-Barré syndrome. Abnormal enhancement in spinal MRI has not been previously described in patients with leukodystrophies. PMID:9744639

Vasconcellos, E; Smith, M

1998-08-01

2

Electrical stimulation of lumbar spinal nerve roots in dogs.  

PubMed

The aim of this study was to test the applicability of electrical stimulation of lumbar spinal nerve roots and obtain normative electrical root stimulation (ERS) data for L7 nerve root and sciatic nerve in dogs. For that purpose ERS and sciatic nerve stimulations were performed consecutively, in totally 40 healthy dogs. ERS was applied in the L7/S1 intervertebral space via monopolar needle electrodes. Muscle responses were recorded from the gastrocnemius muscles on the left and right hind limbs. Sciatic nerve stimulation was performed at the greater trochanter level on the left hind limb, with records obtained from the left gastrocnemius muscle. Mean root latencies of the left and right side were 5.22?±?0.49 ms and 5.29?±?0.53 ms, respectively. There was no significant difference in root latency between the right and left sides. The mean terminal latency was 3.82?±?0.46 ms. The proximal motor nerve conduction velocity of the sciatic nerve was 63.15?±?3.43 m/s. The results of this study show that ERS provides objective data about the integrity of lumbar spinal nerve roots by evaluating the entire population of motor fibres and total length of the motor axon in dogs. ERS can be considered a useful diagnostic method for confirmation of diagnoses of lumbosacral diseases. PMID:24930120

Turan, Erkut; Unsal, Cengiz; Oren, Mehmet Utkan; Dilek, Omer Gurkan; Yildirim, Ismail Gokce; Sarierler, Murat

2014-09-01

3

[Sacral nerve root cysts. Discussion on the mechanism of nerve root suffering. Apropos of 4 cases].  

PubMed

Low back pain, sciatia or perineal chronic pain are sometimes related to perineural sacral cysts. Surgical treatment is difficult and may lead to pain or neurological worsening. We report four cases of symptomatic perineural cysts; three of them where operated on with two good results and one increasing perineal pain. Anatomical and radiological description are reviewed. From a therapeutical point of view, we can distinguish two clinical types of radicular suffering. Perineural cyst can cause a commun radicular extrinsic compression; in such a case surgical operation will improve radicular pain. The cystic nerve root can present an intrinsic suffering because of on intradural dilaceration. Then surgery must be avoided specially when many roots are involved because it may worsen the pluriradicular suffering. PMID:9686226

Bourgeois, P; Gaillard, S; Chastanet, P; Christiaens, J L

1997-01-01

4

Effect of acute nerve root compression on endoneurial fluid pressure and blood flow in rat dorsal root ganglia  

Microsoft Academic Search

The objective of the current study was to test the hypothesis that crush injury to nerve root increases endoneurial fluid pressure (EFP) and decreases blood flow in the associated dorsal root ganglion (DRG). A total of 21 adult, female Sprague–Dawley rats had their left L5 nerve root and DRG exposed. The L5 nerve root was clamped for 2 s with

Tamaki Igarashi; Shoji Yabuki; Shinichi Kikuchi; Robert R. Myers

2005-01-01

5

Median nerve deformation and displacement in the carpal tunnel during finger motion.  

PubMed

The objective of this study was to evaluate the correlations between deformation and displacement of median nerve and flexor tendons during finger motion in the carpal tunnel for both carpal tunnel syndrome (CTS) patients and healthy controls. Sixty-two wrists of 31 asymptomatic volunteers and fifty-one wrists of 28 idiopathic CTS patients were evaluated by ultrasound. The displacement of the median nerve and the middle finger flexor digitorum superficialis (FDS) tendon, as well as area, perimeter, aspect ratio of a minimum enclosing rectangle, and circularity of the median nerve were measured in finger extension and flexion positions. Deformation indices were defined as the ratios of indices in finger extension and flexion positions. The correlations between displacement and deformation indices were evaluated. There were significant correlations between nerve palmar-dorsal displacement and deformation indices (p < 0.05). The aspect ratio deformation index showed the strongest correlation to palmar-dorsal displacement of the nerve (-0.572, p < 0.01). This study showed that there is a relationship between median nerve deformation indices and nerve palmar-dorsal displacement in the carpal tunnel. Since the highest correlations were between palmar-dorsal nerve displacement direction and aspect ratio deformation index, these parameters may be helpful to understand the pathophysiology of CTS. PMID:24038546

Yoshii, Yuichi; Ishii, Tomoo; Tung, Wen-Lin; Sakai, Shinsuke; Amadio, Peter C

2013-12-01

6

Characterization of a chondroitin sulfate hydrogel for nerve root regeneration  

NASA Astrophysics Data System (ADS)

Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

Conovaloff, Aaron; Panitch, Alyssa

2011-10-01

7

Persistent sacral nerve root deficits after continuous spinal anaesthesia  

Microsoft Academic Search

Neurological deficits following spinal anaesthesia are rare. We report two cases of persistent sacral nerve root deficits\\u000a after continuous spinal anaesthesia (CSA) performed with hyperbaric lidocaine through a lumbar microcatheter. In both cases\\u000a the dose of 5% lidocaine (5.7 and 4.3 ml) was greater than usual. In the immediate postoperative period the constellation\\u000a of neurological deficits included perianal hypaesthesia, lower

Randall M. Schell; Floyd S. Brauer; Daniel J. Cole; Richard L. Applegate II

1991-01-01

8

Increased charge displacement in the membrane of myelinated nerve at reduced extracellular pH.  

PubMed Central

Asymmetry currents were measured in nodes of myelinated nerve fibers from Rana esculenta at extracellular pH values of 5.2, 7.0, and 8.1 by averaging the currents during and after 1-ms depolarizing and hyperpolarizing voltage pulses. The charge displacement in the nodal membrane was obtained by numerical integration of the asymmetry currents. Lowering the pH from 7.0 to 5.2 significantly slows down the kinetics of the fast charge displacement during depolarization but hardly affects the kinetics after repolarization. The pH reduction increases the maximum charge displacement during depolarization by 46%. No differences between asymmetry currents were found between pH 7.0 and 8.1. It is concluded that protonation by extracellular H+ ions may increase the net charge or the transition range of mobile subunits in the nerve membrane. PMID:6973369

Neumcke, B; Schwarz, W; Stämpfli, R

1980-01-01

9

Primary choroid plexus papilloma of the sacral nerve roots.  

PubMed

The authors describe a unique case of a choroid plexus papilloma of the sacral nerve roots. This 60-year-old woman was admitted to the hospital because of a 1-year history of sacral pain, rectal and urinary bladder retention, and paradoxical episodic incontinence. Physical examination revealed sensory abnormalities in the S-2 dermatomes and poor rectal and bladder sphincter contractions. Contrast-enhanced spinal MR imaging showed a well-circumscribed, ovoid, homogeneously enhancing mass at the S1-2 level suggesting a diagnosis of ependymoma or schwannoma, and surgery allowed the identification and complete removal of a soft gray mass intimately adhering to the sacral nerve roots. Histological examination revealed a tumor consisting of papillary structures lined by a single layer of columnar cells, with an immunophenotype that satisfied the diagnostic criteria of choroid plexus papilloma. After diagnosis, contrast-enhanced brain MR imaging excluded the presence of a primary choroid plexus papilloma in the cerebral ventricles, thus ruling out a drop metastasis along the CSF pathways. A review of the literature did not reveal any similar cases of choroid plexus papilloma, and so the authors also discuss the inclusion of primary or metastatic papillary tumors in this unusual location as part of the differential diagnosis. PMID:19119933

Boldorini, Renzo; Panzarasa, Gabriele; Girardi, Paola; Monga, Guido

2009-01-01

10

Radiological anatomical consideration of conjoined nerve root with a case review  

PubMed Central

Nerve root anomalies are frequently underrecognized regardless of the advances in imaging studies; they are also underappreciated and underreported when encountered surgically. The classification of conjoined nerve roots is based on whether the nerve root emerges at an abnormal level or from an anastomotic branch. In the present report, we describe case with a conjoined nerve root that emerged at a more caudal level than that normally observed that was an undiagnosed on preoperative imaging studies. We also discuss the atypical imaging features obtained through preoperative imaging studies. As observed in the present case, preoperative recognition and diagnosis of such anomalies offer the best opportunity of performing a successful procedure and preventing inadvertent damage to nerve roots intraoperatively. PMID:24386602

Oh, Chang Hyun; Park, Jae Suk; Choi, Won-Seok; Choi, Eunhwa

2013-01-01

11

Repair of ruptured spinal nerve roots in a brachial plexus lesion. Case report.  

PubMed

A 22-year-old woman sustained a brachial plexus injury with supraganglionic rupture of the C-8 and T-1 nerve roots as a result of a traffic accident. She was operated on approximately 1 week following the accident. After a hemilaminectomy, the intradural defects in the ruptured roots were bridged with sural nerve grafts. Within 3 years she recovered function in all muscles supplied from the lower roots in the plexus except for the intrinsic hand muscles, but she had a persisting, complete sensory loss in the ulnar nerve distribution. The possibility for functional gain after repair of spinal root lesions in brachial plexus patients is discussed. PMID:7897534

Carlstedt, T; Norén, G

1995-04-01

12

Brachial Plexopathy/Nerve Root Avulsion in a Football Player: The Role of Electrodiagnostics  

PubMed Central

Electromyography (EMG) studies are a useful tool in anatomical localization of peripheral nerve and brachial plexus injuries. They are especially helpful in distinguishing between brachial plexopathy and nerve root injuries where surgical intervention may be indicated. EMG can also assist in providing prognostic information after nerve injury as well as after nerve repair. In this case report, a football player presented with weakness in his right upper limb after a traction/traumatic injury to the right brachial plexus. EMG studies revealed evidence of both pre- and postganglionic injury to multiple cervical roots. The injury was substantial enough to cause nerve root avulsions involving the C6 and C7 levels. Surgical referral led to nerve grafts targeted at regaining function in shoulder abduction and elbow flexion. After surgery, the patient’s progress was monitored utilizing EMG to assist in identifying true axonal regeneration. PMID:18751870

Radecki, Jeffrey; Wolfe, Scott W.; Strauss, Helene L.; Mintz, Douglas N.

2008-01-01

13

Prolonged electrical stimulation causes no damage to sacral nerve roots in rabbits  

PubMed Central

Previous studies have shown that, anode block electrical stimulation of the sacral nerve root can produce physiological urination and reconstruct urinary bladder function in rabbits. However, whether long-term anode block electrical stimulation causes damage to the sacral nerve root remains unclear, and needs further investigation. In this study, a complete spinal cord injury model was established in New Zealand white rabbits through T9–10 segment transection. Rabbits were given continuous electrical stimulation for a short period and then chronic stimulation for a longer period. Results showed that compared with normal rabbits, the structure of nerve cells in the anterior sacral nerve roots was unchanged in spinal cord injury rabbits after electrical stimulation. There was no significant difference in the expression of apoptosis-related proteins such as Bax, Caspase-3, and Bcl-2. Experimental findings indicate that neurons in the rabbit sacral nerve roots tolerate electrical stimulation, even after long-term anode block electrical stimulation. PMID:25206785

Yan, Peng; Yang, Xiaohong; Yang, Xiaoyu; Zheng, Weidong; Tan, Yunbing

2014-01-01

14

Primary glioblastoma of the trigeminal nerve root entry zone: case report.  

PubMed

Gliomas of the cranial nerve root entry zone are rare clinical entities. There have been 11 reported cases in the literature, including only 2 glioblastomas. The authors report the case of a 67-year-old man who presented with isolated facial numbness and was found to have a glioblastoma involving the trigeminal nerve root entry zone. After biopsy the patient completed treatment with conformal radiation and concomitant temozolomide, and at 23 weeks after surgery he demonstrated symptom progression despite the treatment described. This is the first reported case of a glioblastoma of the trigeminal nerve root entry zone. PMID:25380115

Breshears, Jonathan D; Ivan, Michael E; Cotter, Jennifer A; Bollen, Andrew W; Theodosopoulos, Phillip V; Berger, Mitchel S

2015-01-01

15

Ultrasonographic cross-sectional area of spinal nerve roots in cervical radiculopathy: a pilot study.  

PubMed

Recently, sonographic assessment has been considered an alternative method for evaluating cervical root lesions. The aim of this pilot study was to measure cross-sectional areas (CSAs) of cervical spinal nerve roots using high-resolution ultrasonography in patients with cervical radiculopathy, to compare the CSA of nerve roots between the affected and unaffected sides. Patients with a clinical diagnosis of unilateral cervical radiculopathy, who were referred to the Department of Physical Medicine and Rehabilitation in the University General Hospital by general practitioners, were prospectively recruited. The selected nerve roots were sonographically imaged at the most proximal location possible, where they exited over the transverse processor, just distal to that point. The CSA was measured three times using the trace tool available on the ultrasonography device. The CSA of each contralateral nerve root served as a control. Twenty-four patients (9 women; mean age, 53.7 yrs) were enrolled in this study. The CSAs were measured by ultrasonography in 5 pairs of C5 roots, 12 pairs of C6 roots, and 7 pairs of C7 roots. The mean CSAs of the affected and unaffected sides were 9.74 ± 1.95 and 9.47 ± 1.95 mm, respectively (P = 0.019). Spearman rank-order correlation test showed a positive relationship between the CSA of the affected nerve root and the duration of symptoms (?22 = 0.467, P = 0.021).This is, to the authors' knowledge, the first comparative study to obtain the CSA of spinal nerve roots in cervical radiculopathy. Increased CSA of the affected nerve root relative to the unaffected side, as demonstrated by ultrasonography, may be useful as an additive clue for the diagnosis of cervical radiculopathy. PMID:25415392

Kim, Eunkuk; Yoon, Joon-Shik; Kang, Hyo Jung

2015-02-01

16

The Relation Between Rotation Deformity and Nerve Root Stress in Lumbar Scoliosis  

NASA Astrophysics Data System (ADS)

Even though several finite element models of lumbar spine were introduced, there has been no model including the neural structure. Therefore, the authors made the novel lumbar spine finite element model including neural structure. Using this model, we investigated the relation between the deformity pattern and nerve root stress. Two lumbar models with different types of curve pattern (lateral bending and lateral bending with rotation curve) were made. In the model of lateral bending curves without rotation, the principal compressive nerve root stress on the concave side was greater than the principal tensile stress on the convex side at the apex vertebra. Contrarily, in the lateral bending curve with rotational deformity, the nerve stress on the convex side was higher than that on the concave side. Therefore, this study elicit that deformity pattern could have significantly influence on the nerve root stress in the lumbar spine.

Kim, Ho-Joong; Lee, Hwan-Mo; Moon, Seong-Hwan; Chun, Heoung-Jae; Kang, Kyoung-Tak

17

Co-occurrence of lumbar spondylolysis and lumbar disc herniation with lumbosacral nerve root anomaly  

PubMed Central

Lumbosacral nerve root anomalies are the leading cause of lumbar surgery failures. Although co-occurrence of lumbar spondylolysis and disc herniation is common, it is very rare to observe that a nerve root anomaly accompanies these lesions. A 49-year-old male patient presented with sudden-onset right leg pain. Examinations revealed L5/S1 lumbar spondylolysis and disc herniation. At preoperative period, he was also diagnosed with lumbosacral root anomaly. Following discectomy and root decompression, stabilization was performed. The complaints of the patient diagnosed with lumbosacral root anomaly at intraoperative period were improved at postoperative period. It should be remembered that in patients with lumbar disc herniation and spondylolysis, lumbar root anomalies may coexist when clinical and neurological picture is severe. Preoperative and perioperative assessments should be made meticulously to prevent neurological injury. PMID:25210343

Y?lmaz, Tevfik; Turan, Yahya; Gül?en, ?smail; Dalbayrak, Sedat

2014-01-01

18

A stereological study of dorsal root ganglion cells and nerve root fibers from rats exposed to mercury vapor  

Microsoft Academic Search

Although mercury vapor is known to produce tremor and peripheral neuropathy, neuropathological studies of the effects of\\u000a the vapor are few in number. The aim of the present study has been to evaluate the effect of mercury vapor on the morphology\\u000a of the dorsal root ganglion and the spinal nerve roots. Adult male rats were exposed to mercury vapor for

Jørgen Drasbæk Schiønning; Jytte Overgaard Larsen; Rune Eide

1998-01-01

19

Return of function after spinal cord implantation of avulsed spinal nerve roots.  

PubMed

Avulsion of nerve roots from the spinal cord is widely regarded as an untreatable injury. However, a series of experiments in animals has shown that, if continuity is restored between spinal cord and ventral roots, axons from spinal motor neurons can regrow into the peripheral nerves with recovery of motor function. These observations were applied in the treatment of a man with avulsion of the 6th cervical (C6) to 1st thoracic roots due to brachial plexus injury. Two ventral roots were implanted into the spinal cord through slits in the pia mater, C6 directly and C7 via sural nerve grafts. Voluntary activity in proximal arm muscles was detected electromyographically after nine months and clinically after one year. After three years the patient had voluntary activity (with some co-contraction) in the deltoid, biceps, and triceps muscles. To determine whether the improvement was due to spontaneous recovery from C5, the C5 root was blocked pharmacologically, and the results indicated that the repaired roots were contributing substantially to motor function. Repair of spinal nerve roots deserves further exploration in management of brachial plexus injury. PMID:7475770

Carlstedt, T; Grane, P; Hallin, R G; Norén, G

1995-11-18

20

Development of a duration threshold for modulating evoked neuronal responses after nerve root compression injury.  

PubMed

Cervical nerve roots are susceptible to compression injuries of various durations. The duration of an applied compression has been shown to contribute to both the onset of persistent pain and also the degree of spinal cellular and molecular responses related to nociception. This study investigated the relationship between peripherally-evoked activity in spinal cord neurons during a root compression and the resulting development of axonal damage. Electrically-evoked spikes were measured in the spinal cord as a function of time during and after (post-compression) a 15 minute compression of the C7 nerve root. Compression to the root significantly (p=0.035) reduced the number of spikes that were evoked over time relative to sham. The critical time for compression to maximally reduce evoked spikes was 6.6±3.0 minutes. A second study measured the post- compression evoked neuronal activity following compression applied for a shorter, sub-threshold time (three minutes). Ten minutes after compression was removed, the discharge rate remained significantly (p=0.018) less than baseline by 58±25% relative to sham after the 15 minute compression, but returned to within 3±33% of baseline after the three minute compression. Axonal damage was evident in the nerve root at day seven after nerve root compression only after a 15 minute compression. These studies demonstrate that even a transient mechanical insult to the nerve root is sufficient to induce sustained neuronal dysfunction and axonal pathology associated with pain, and results provide support that such minor neural tissue traumas can actually induce long-lasting functional deficits. PMID:22869302

Nicholson, Kristen J; Quindlen, Julia C; Winkelstein, Beth A

2011-11-01

21

Scanning pattern of diffusion tensor tractography and an analysis of the morphology and function of spinal nerve roots  

PubMed Central

Radiculopathy, commonly induced by intervertebral disk bulging or protrusion, is presently diagnosed in accordance with clinical symptoms because there is no objective quantitative diagnostic criterion. Diffusion tensor magnetic resonance imaging and diffusion tensor tractography revealed the characterization of anisotropic diffusion and displayed the anatomic form of nerve root fibers. This study included 18 cases with intervertebral disc degeneration-induced unilateral radiculopathy. Magnetic resonance diffusion tensor imaging was creatively used to reveal the scanning pattern of fiber tracking of the spinal nerve root. A scoring system of nerve root morphology was used to quantitatively assess nerve root morphology and functional alteration after intervertebral disc degeneration. Results showed that after fiber tracking, compared with unaffected nerve root, fiber bundles gathered together and interrupted at the affected side. No significant alteration was detected in the number of fiber bundles, but the cross-sectional area of nerve root fibers was reduced. These results suggest that diffusion tensor magnetic resonance imaging-based tractography can be used to quantitatively evaluate nerve root function according to the area and morphology of fiber bundles of nerve roots. PMID:25206637

Tian, Xin; Liu, Huaijun; Geng, Zuojun; Yang, Hua; Wang, Guoshi; Yang, Jiping; Wang, Chunxia; Li, Cuining; Li, Ying

2013-01-01

22

Peripheral nerve injury triggers noradrenergic sprouting within dorsal root ganglia  

Microsoft Academic Search

IN humans, trauma to a peripheral nerve may be followed by chronic pain syndromes which are only relieved by blockade of the effects of sympathetic impulse traffic1-4. It is presumed that, after the lesion, noradrenaline released by activity of sympathetic postganglionic axons excites primary afferent neurons by activating alpha-adrenoceptors2,5, generating signals that enter the 'pain pathways' of the central nervous

Elspeth M. McLachlan; Wilfrid Jänig; Marshall Devor; Martin Michaelis

1993-01-01

23

Selective Lumbar Nerve Root Blocks with CT Fluoroscopic Guidance: Technique, Results, Procedure Time, and Radiation Dose  

Microsoft Academic Search

Summary: CT fluoroscopy may be used as a rapid and effective means of guiding needle placement when perform- ing selective lumbar nerve root blocks. In this set of pa- tients, the average external radiation dose was 0.73 mrem per procedure, with an average of 2 seconds of CT-fluoros- copy time and four images per procedure. Average physi- cian room time

Andrew L. Wagner

24

Percutaneous magnetic coil stimulation of the phrenic nerve roots and trunk  

Microsoft Academic Search

We describe a technique of percutaneous magnetic coil NO stimulation of the phrenic nerve trunk on one side of the neck and phrenic roots over the upper cervical vertebral column in 10 normal subjects and 2 patients. We were able to obtain compound muscle action potentials (CMAPs) from the diaphragm at two sites (xiphoid process and 7th intercostal space) after

S. Chokroverty; S. Shah; M. Chokroverty; A. Deutsch; J. Belsh

1995-01-01

25

Lack of effectiveness of laser therapy applied to the nerve course and the correspondent medullary roots  

PubMed Central

OBJECTIVE: To investigate the influence of low intensity laser irradiation on the regeneration of the fibular nerve of rats after crush injury. METHODS: Twenty-five rats were used, divided into three groups: 1) intact nerve, no treatment; 2) crushed nerve, no treatment; 3) crush injury, laser irradiation applied on the medullary region corresponding to the roots of the sciatic nerve and subsequently on the course of the damaged nerve. Laser irradiation was carried out for 14 consecutive days. RESULTS: Animals were evaluated by functional gait analysis with the peroneal functional index and by histomorphometric analysis using the total number of myelinated nerve fibers and their density, total number of Schwann cells, total number of blood vessels and the occupied area, minimum diameter of the fiber diameter and G-quotient. CONCLUSION: According to the statistical analysis there was no significant difference among groups and the authors conclude that low intensity laser irradiation has little or no influence on nerve regeneration and functional recovery. Laboratory investigation. PMID:24453650

Sousa, Fausto Fernandes de Almeida; Ribeiro, Thaís Lopes; Fazan, Valéria Paula Sassoli; Barbieri, Claudio Henrique

2013-01-01

26

Novel surgical strategies to correct neural deficits following experimental spinal nerve root lesions.  

PubMed

In attempts to correct neural deficits following avulsion trauma, novel experimental strategies were developed. In rats, spinal roots were replanted superficially in the dorsal horn following dorsal root avulsion and concomitant denervation by ganglionectomy. Outgrowth from cord neurons in the dorsal horn into the implanted dorsal root was demonstrated by means of retrograde HRP labeling. Double labeling experiments showed that some of these neurons had retained their central projections while extending new processes into the implanted root. After dorsal root avulsion, sensory pathways might be reconstructed by substituting the lost input from damaged primary sensory neurons with induced peripheral outgrowths from secondary neurons. In primates, intraspinal replantation of avulsed ventral nerve roots was investigated as a surgical treatment for motor deficits that develop after severe brachial plexus injury. Two to 3 months after surgery there were EMG signs of reinnervation in previously denervated muscles, which were shortly followed by evidence of clinical recovery. A gradual improvement in the function of the affected arm occurred and motor behavior became normalized, although the EMG activity in the reinnervated muscles at maximal contraction was still reduced. The outcome of these experimental studies indicates that reconstructive surgery applied to the brachial plexus might be of value to restore functional deficits induced by traumatic spinal nerve root avulsions also in man. PMID:8457894

Carlstedt, T; Aldskogius, H; Hallin, R G; Nilsson-Remahl, I

1993-01-01

27

Migratory Reed Warblers Need Intact Trigeminal Nerves to Correct for a 1,000 km Eastward Displacement  

PubMed Central

Several studies have shown that experienced night-migratory songbirds can determine their position, but it has remained a mystery which cues and sensory mechanisms they use, in particular, those used to determine longitude (east–west position). One potential solution would be to use a magnetic map or signpost mechanism like the one documented in sea turtles. Night-migratory songbirds have a magnetic compass in their eyes and a second magnetic sense with unknown biological function involving the ophthalmic branch of the trigeminal nerve (V1). Could V1 be involved in determining east–west position? We displaced 57 Eurasian reed warblers (Acrocephalus scirpaceus) with or without sectioned V1. Sham operated birds corrected their orientation towards the breeding area after displacement like the untreated controls did. In contrast, V1-sectioned birds did not correct for the displacement. They oriented in the same direction after the displacement as they had done at the capture site. Thus, an intact ophthalmic branch of the trigeminal nerve is necessary for detecting the 1,000 km eastward displacement in this night-migratory songbird. Our results suggest that V1 carries map-related information used in a large-scale map or signpost sense that the reed warblers needed to determine their approximate geographical position and/or an east–west coordinate. PMID:23840374

Heyers, Dominik; Mouritsen, Henrik

2013-01-01

28

Nerve root anomalies: implications for transforaminal lumbar interbody fusion surgery and a review of the Neidre and Macnab classification system.  

PubMed

Lumbar nerve root anomalies are uncommon phenomena that must be recognized to avoid neural injury during surgery. The authors describe 2 cases of nerve root anomalies encountered during mini-open transforaminal lumbar interbody fusion (TLIF) surgery. One anomaly was a confluent variant not previously classified; the authors suggest that this variant be reflected in an amendment to the Neidre and Macnab classification system. They also propose strategies for identifying these anomalies and avoiding injury to anomalous nerve roots during TLIF surgery. Case 1 involved a 68-year-old woman with a 2-year history of neurogenic claudication. An MR image demonstrated L4-5 stenosis and spondylolisthesis and an L-4 nerve root that appeared unusually low in the neural foramen. During a mini-open TLIF procedure, a nerve root anomaly was seen. Six months after surgery this patient was free of neurogenic claudication. Case 2 involved a 60-year-old woman with a 1-year history of left L-4 radicular pain. Both MR and CT images demonstrated severe left L-4 foraminal stenosis and focal scoliosis. Before surgery, a nerve root anomaly was not detected, but during a unilateral mini-open TLIF procedure, a confluent nerve root was identified. Two years after surgery, this patient was free of radicular pain. PMID:23905960

Burke, Shane M; Safain, Mina G; Kryzanski, James; Riesenburger, Ron I

2013-08-01

29

Lumbar nerve root compression due to extradural, intraforaminal lipoma. An underdiagnosed entity?  

PubMed

Intraspinal extradural lipomas, not associated with spinal dysraphism, are rare lesions. True adult lipomas have to be distinguished from angiolipomas and from epidural lipomatosis. The authors report a unique case of a patient with unilateral lumbar nerve root compression caused by extradural, intraforaminal, true adult lipoma. A 62-year-old woman suffered severe left L-5 radiculopathy that progressively worsened during the 12 months prior to presentation. She did not experience improvement with conservative therapy. An MR imaging study of the lumbar spine revealed shifting of the left L-5 nerve root caused by a small extradural intrarecessal (that is, the beginning of the intravertebral foramen)/intraforaminal mass with MR imaging characteristics of fatty tissue. No other relevant intraspinal pathology could be identified. A left L4-5 fenestration was carried out. A small fatty intrarecessal/intraforaminal mass compressing severely the left L-5 root was identified and completely resected. The histological examination revealed a lipoma. The patient recovered completely and is fully mobile and symptom free 1 year after the operation. Intraspinal lipomas should be considered in cases of radiculopathy, especially in the absence of relevant degenerative or tumorous pathology and in the presence of nerve root shifting caused by fatty tissue. PMID:18976170

Zevgaridis, Dimitris; Nanassis, Kimon; Zaramboukas, Thomas

2008-11-01

30

Computerized tomography myelography with coronal and oblique coronal view for diagnosis of nerve root avulsion in brachial plexus injury  

Microsoft Academic Search

BACKGROUND: The authors describe a new computerized tomography (CT) myelography technique with coronal and oblique coronal view to demonstrate the status of the cervical nerve rootlets involved in brachial plexus injury. They discuss the value of this technique for diagnosis of nerve root avulsion compared with CT myelography with axial view. METHODS: CT myelography was performed with penetration of the

Hiroshi Yamazaki; Kazuteru Doi; Yasunori Hattori; Sotetsu Sakamoto

2007-01-01

31

Painful nerve injury upregulates thrombospondin-4 expression in dorsal root ganglia.  

PubMed

Thrombospondin-4 (TSP4) belongs to a family of large, oligomeric extracellular matrix glycoproteins that mediate interactions between cells and interactions of cells with underlying matrix components. Recent evidence shows that TSP4 might contribute to the generation of neuropathic pain. However, there has been no systematic examination of TSP4 expression in the dorsal root ganglia (DRG) after injury. This study, therefore, investigates whether TSP4 protein level is changed in DRG after injury following spinal nerve ligation (SNL) and spared nerve injury in rats by performing Western blotting, immunohistochemistry, and immunocytochemistry. After nerve ligation, TSP4 protein level is upregulated in the axotomized somata of the fifth lumbar (L5) DRG. There is substantial additional TSP4 in the nonneuronal compartment of the L5 DRG that does not costain for markers of satellite glia, microglia, or Schwann cells and appears to be in the interstitial space. Evidence of intracellular overexpression of TSP4 persists in neurons dissociated from the L5 DRG after SNL. These findings indicate that, following peripheral nerve injury, TSP4 protein expression is elevated in the cytoplasm of axotomized sensory neurons and in the surrounding interstitial space. © 2014 Wiley Periodicals, Inc. PMID:25327416

Pan, Bin; Yu, Hongwei; Park, John; Yu, Yanhui Peter; Luo, Z David; Hogan, Quinn H

2015-03-01

32

Spinal nerve root injuries in brachial plexus lesions: basic science and clinical application of new surgical strategies. A review.  

PubMed

This paper reviews studies aimed at developing novel surgical means to correct functional deficits after spinal nerve root injuries in brachial plexus lesions. In a long series of animal experiments it has been possible to demonstrate re-established connectivity between severed roots and the damaged spinal cord segment. This encouraging functional recovery by a new surgical strategy of managing ventral root avulsion injuries prompted clinical application, with restoration of activity. PMID:7658961

Carlstedt, T P

1995-01-01

33

Resection of a pelvic schwannoma with partial removal of the sacral nerve root.  

PubMed

Because the symptoms do not appear in most cases until the tumor has grown quite large, schwannomas are often detected incidentally during work-up for some other condition. Benign schwannomas generally do not invade adjacent structures but making the diagnosis preoperatively can be difficult when the tumor is large. We report the case of a benign schwannoma which was diagnosed preoperatively by needle core biopsy under computed tomography guidance. The tumor was removed completely by partially resecting the S1 nerve root, which was subsequently reanastomosed. The postoperative course was uneventful with the exception of minimal left leg pain due to neurologic deficit. PMID:12630001

Otsuji, Eigo; Hagiwara, Akeo; Toma, Atsushi; Urasaki, Koji; Tsuchihashi, Yasunari; Yamagishi, Hisakazu

2003-01-01

34

Laparoscopic management of sacral nerve root schwannoma with intractable vulvococcygodynia: report of three cases and review of literature.  

PubMed

Herein we report the feasibility of laparoscopic resection of schwannomas of the sacral nerves roots in 3 women with intractable vulvodynia and coccygodynia. Laparoscopic en bloc resection of the sacral schwannomas was performed, with primary control of the tumor blood supply and with exposure and sparing of the sacral nerve roots. In all 3 patients, laparoscopy was successful, with minimal blood loss and without complications. Histologic examination confirmed the diagnosis of schwannoma without malignant transformation in all 3 women. At mean follow-up of 27.66 months, no patient reported recurrence or worsening of symptoms. All patients are able to walk normally without gait aids. Primary control of the tumor blood supply during laparoscopic surgery to resect deep sacral masses reduces considerably the risk of operative hemorrhage. Compared with classic neurosurgical approaches, laparoscopic exposure of the rectum, ureters, and sacral nerve roots renders the procedure safer and easier, with less risk of postoperative functional morbidity. PMID:23522662

Possover, Marc; Kostov, Plamen

2013-01-01

35

Confocal imaging reveals three-dimensional fine structure difference between ventral and dorsal nerve roots  

NASA Astrophysics Data System (ADS)

Peripheral nerve injury repair is one of the most challenging problems in neurosurgery, partially due to lack of knowledge of three-dimensional (3-D) fine structure and organization of peripheral nerves. In this paper, we explored the structures of nerve fibers in ventral and dorsal nerves with a laser scanning confocal microscopy. Thick tissue staining results suggested that nerve fibers have a different 3-D structure in ventral and dorsal nerves, and reconstruction from serial sectioning images showed that in ventral nerves the nerve fibers travel in a winding form, while in dorsal nerves, the nerve fibers form in a parallel cable pattern. These structural differences could help surgeons to differentiate ventral and dorsal nerves in peripheral nerve injury repair, and also facilitate scientists to get a deeper understanding about nerve fiber organization.

Wu, Yuxiang; Sui, Tao; Cao, Xiaojian; Lv, Xiaohua; Zeng, Shaoqun; Sun, Peng

2011-05-01

36

The Accuracy of the Physical Examination for the Diagnosis of Midlumbar and Low Lumbar Nerve Root Impingement  

PubMed Central

Study Design Cross-sectional study with prospective recruitment. Objective To determine the accuracy of the physical examination for the diagnosis of midlumbar nerve root impingement (L2, L3, or L4), low lumbar nerve root impingement (L5 or S1) and level-specific lumbar nerve root impingement on magnetic resonance imaging (MRI), using individual tests and combinations of tests. Summary of Background Data The sensitivity and specificity of the physical examination for the localization of nerve root impingement has not been previously studied. Methods Sensitivities, specificities and LRs were calculated for the ability of individual tests and test combinations to predict the presence or absence of nerve root impingement at midlumbar, low lumbar, and specific nerve root levels. Results LRs ?5.0 indicate moderate to large changes from pre-test probability of nerve root impingement to post-test probability. For the diagnosis of midlumbar impingement, the femoral stretch test (FST), crossed femoral stretch test (CFST), medial ankle pinprick sensation, and patellar reflex testing demonstrated LRs ?5.0 (LR ?). LRs ?5.0 were seen with the combinations of FST and either patellar reflex testing (LR 7.0; 95% CI 2.3–21), or the sit-to-stand test (LR ?). For the diagnosis of low lumbar impingement, the Achilles reflex test demonstrated a LR ?5.0 (LR 7.1; CI 0.96–53); test combinations did not increase LRs. For the diagnosis of level-specific impingement, LRs ?5.0 were seen for anterior thigh sensation at L2 (LR 13; 95% CI 1.8–87); FST at L3 (LR 5.7 ; 95% CI 2.3–4.4); patellar reflex testing (LR 7.7; 95% CI 1.7–35), medial ankle sensation (LR ?), or CFST (LR 13; 95% CI 1.8–87) at L4; and hip abductor strength at L5(LR 11; 95% CI 1.3–84). Test combinations increased LRs for level-specific root impingement at the L4 level only. Conclusions Individual physical examination tests may provide clinical information which substantially alters the likelihood that midlumbar impingement, low lumbar impingement, or level-specific impingement is present. Test combinations improve diagnostic accuracy for midlumbar impingement. PMID:20543768

Suri, Pradeep; Rainville, James; Katz, Jeffrey N.; Jouve, Cristin; Hartigan, Carol; Limke, Janet; Pena, Enrique; Li, Ling; Swaim, Bryan; Hunter, David J

2010-01-01

37

Time Course of Substance P Expression in Dorsal Root Ganglia Following Complete Spinal Nerve Transection  

PubMed Central

Recent evidence suggests that substance P (SP) is upregulated in primary sensory neurons following axotomy, and that this change occurs in larger neurons that do not usually produce SP. If so, this upregulation may allow normally neighboring, uninjured, and non-nociceptive dorsal root ganglion (DRG) neurons to become effective in activating pain pathways. Using immunohistochemistry, we performed a unilateral L5 spinal nerve transection upon male Wistar rats, and measured SP expression in ipsilateral L4 and L5 DRGs and contralateral L5 DRGs, at 1 to 14 days postoperatively (dpo), and in control and sham operated rats. In normal and sham operated DRGs, SP was detectable almost exclusively in small neurons (? 800 ?m2). Following surgery, the mean size of SP-positive neurons from the axotomized L5 ganglia was greater at 2, 4, 7 and 14 dpo. Among large neurons (> 800 ?m2) from the axotomized L5, the percentage of SP-positive neurons increased at 2, 4, 7, and 14 dpo. Among small neurons from the axotomized L5, the percentage of SP-positive neurons was increased at 1 and 3 dpo, but was decreased at 7 and 14 dpo. Thus, SP expression is affected by axonal damage, and the time course of the expression is different between large and small DRG neurons. These data support a role of SP-producing, large DRG neurons in persistent sensory changes due to nerve injury. PMID:16680762

Weissner, Wendy; Winterson, Barbara J.; Stuart-Tilley, Alan; Devor, Marshall; Bove, Geoffrey M.

2008-01-01

38

Fluoroscopically guided infiltration of the cervical nerve root: an indirect approach through the ipsilateral facet joint.  

PubMed

Transforaminal infiltrations in the cervical spine are governed by a higher rate of vascular puncture than in the lumbar spine. The purpose of our study is to assess the safety and efficacy of percutaneous, fluoroscopically guided nerve root infiltrations in cases of cervical radiculopathy. An indirect postero-lateral approach was performed through the ipsilateral facet joint. During the last 2 years, 25 patients experiencing cervical radiculopathy underwent percutaneous, fluoroscopically guided nerve root infiltrations by means of an indirect postero-lateral approach through the ipsilateral facet joint. The intra-articular position of the needle (22-gauge spinal needle) was fluoroscopically verified after injection of a small amount of contrast medium which also verified dispersion of the contrast medium periradicularly and in the epidural space. Then a mixture of long-acting glucocorticosteroid diluted in normal saline (1.5/1 mL) was injected intra-articularly. A questionnaire with a Numeric Visual Scale (NVS) scale helped assess pain relief, life quality, and mobility improvement. A mean of 2.3 sessions was performed in the patients of our study. In the vast majority of our patients 19/25 (76%), the second infiltration was performed within 7-10 days of the first one. Comparing the pain scores prior (mean value 8.80 ± 1.080 NVS units) and after (mean value 1.84 ± 1.405 NVS units), there was a mean decrease of 6.96 ± 1.695 NVS units [median value 7 NVS units (P < 0.001) in terms of pain reduction, effect upon mobility, and life quality. There were no clinically significant complications noted in our study. Fluoroscopically guided transforaminal infiltrations through the ipsilateral facet joint seem to be a feasible, efficacious, and safe approach for the treatment of patients with cervical radiculopathy. This approach facilitates needle placement and minimizes risk of complications. PMID:25054388

Kelekis, Alexios; Filippiadis, Dimitrios K; Velonakis, Georgios; Martin, Jean-Baptist; Oikonomopoulos, Nikolaos; Brountzos, Elias; Kelekis, Nikolaos

2014-01-01

39

Irreducible dorsal distal radius fracture-dislocation with accompanying dorsal displacement of flexor tendons and median nerve: A rare type of injury  

PubMed Central

INTRODUCTION High energy distal radius fractures may cause significant soft tissue injuries. Dorsal displacement of median nerve and flexor tendons to dorsal compartment between distal radioulnar joint was an unreported type of soft tissue injury. PRESENTATION OF CASE 35-Year male admitted following fall from height diagnosed as closed distal radius fracture with dorsal displacement. The patient had no flexion and extension of all fingers with loss of sensation. Radial artery pulse was not palpable. Radiography and CT imaging revealed distal radius fracture with dorsal displacement with dorsal carpal dislocation. After failure of closed reduction, operative treatment was performed. At surgery, flexor tendons and median nerve was found to be placed at dorsal compartment. Reduction of the soft tissues was facilitated by distraction of distal radioulnar joint. DISCUSSION Dorsal displacement of volar structures as the result of fracture dislocation was found to be an unreported type of injury. Difficulty during reduction of dorsally displaced structures is an important feature of the case. CONCLUSION For severely displaced and deformed distal radial fractures and fracture dislocations, threshold for operative treatment should be kept low. PMID:25460459

Songür, Murat; ?ahin, Ercan; Zehir, Sinan; Kalem, Mahmut

2014-01-01

40

Root negative gravitropism is accompanied with displacing of columella amyloplasts to the statocyte upper longitudinal cell wall  

NASA Astrophysics Data System (ADS)

Recently it was shown that roots reveal negative gravitropism in the weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Ca2+ ions. A negative gravitropic reaction in the CMF occurs by a usual physiological process. Experiments in the CMF confirmed that gravitropism is plastid-based and Ca2+ ions participate in this process. Unlike control, amyloplasts-statoliths are not displacing on the lower side of a gravistimulated root but tend to group in the center of a statocyte during 30 min under gravistimulation in the CMF. In an hour of gravistimulation, they are localized near one of the statocyte longitudinal wall. Now we determined that amyloplasts are localized along the statocyte upper longitudinal side. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. On the basis of the obtained data there is a question, what forces promote displacing of amyloplasts against a gravitational vector? In the paper, three possible explanations are discussed: 1) CMF + Ca2+ action on the distribution of elastic forces in cytoskeleton, 2) CMF + Ca2+ action on the distribution of electric field in statocytes, and 3) CMF action on energy and direction of Ca2+ ion rotation according to the ion cyclotron resonance model that can lead to paradoxical Ca2+ redistribution.

Kordyum, Elizabeth; Sobol, Margaryta; Kalinina, Yana; Bogatina, Nina; Kondrachuk, Alexander

41

Oxygen-ozone therapy for herniated lumbar disc in patients with subacute partial motor weakness due to nerve root compression.  

PubMed

Intradiscal oxygen-ozone (O2-O3) chemonucleolysis is a well-known effective treatment for pain caused by protruding disc disease and nerve root compression due to bulging or herniated disc. The most widely used therapeutic combination is intradiscal injection of an O2-O3 mixture (chemonucleolysis), followed by periradicular injection of O2-O3, steroid and local anaesthetic to enhance the anti-inflammatory and analgesic effect. The treatment is designed to resolve pain and is administered to patients without motor weakness, whereas patients with acute paralysis caused by nerve root compression undergo surgery 24-48h after the onset of neurological deficit. This paper reports on the efficacy of O2-O3 chemonucleolysis associated with anti-inflammatory foraminal injection in 13 patients with low back pain and cruralgia, low back pain and sciatica and subacute partial motor weakness caused by nerve root compression unresponsive to medical treatment. All patients were managed in conjunction with our colleagues in the Neurosurgery Unit of Bellaria Hospital and the IRCCS Institute of Neurological Sciences, Bologna. The outcomes obtained are promising: 100% patients had a resolution of motor weakness, while 84.6% had complete pain relief. Our results demonstrate that O2-O3 therapy can be considered a valid treatment option for this category of patients. PMID:25363257

Dall'Olio, Massimo; Princiotta, Ciro; Cirillo, Luigi; Budai, Caterina; de Santis, Fabio; Bartolini, Stefano; Serchi, Elena; Leonardi, Marco

2014-10-31

42

Brain-derived neurotrophic factor expression in dorsal root ganglion neurons in response to reanastomosis of the distal stoma after nerve grafting?  

PubMed Central

Studies have shown that retreatment of the distal stoma after nerve grafting can stimulate nerve regeneration. The present study attempted to verify the effects of reanastomosis of the distal stoma, after nerve grafting, on nerve regeneration by assessing brain-derived neurotrophic factor expression in 2-month-old rats. Results showed that brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after autologous nerve grafting post sciatic nerve injury, peaked at 14 days, decreased at 28 days, and reached similar levels to the sham-surgery group at 56 days. Brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after reanastomosis of the distal stoma, 59 days after autologous nerve grafting post sciatic nerve injury, significantly increased at 63 days, peaked at 70 days, and gradually decreased thereafter, but remained higher compared with the sham-surgery group up to 112 days. The results of this study indicate that reanastomosis of the distal stoma after orthotopic nerve grafting stimulated brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia.

Yu, Wei; Wang, Jian; Xu, Mingzhu; Qin, Hanjiao; Cui, Shusen

2012-01-01

43

Surgical treatment for total root avulsion type brachial plexus injuries by neurotization: A prospective comparison study between total and hemicontralateral C7 nerve root transfer  

PubMed Central

Purpose: We conducted a clinical study to evaluate the effects of neurotization, especially comparing the total contralateral C7 (CC7) root transfer to hemi-CC7 transfer, on total root avulsion brachial plexus injuries (BPI). Methods: Forty patients who received neurotization for BPI were enrolled in this prospective study. Group 1 (n = 20) received hemi-CC7 transfer for hand function, while group 2 (n = 20) received total-CC7 transfer. Additional neurotization included spinal accessory, phrenic, and intercostal nerve transfer for shoulder and elbow function. The results were evaluated with an average of 6 years follow-up. Results: Group 1 had fewer donor site complications (15%) than group 2 (45%); group 2 had significantly better hand M3 and M4 motor function (65%) than group 1 (30%; P = 0.02). There was no difference in sensory recovery. Significantly, better shoulder function was obtained by simultaneous neurotization on both suprascapular and axillary nerves. Conclusions: Total-CC7 transfer had better hand recovery but more donor complications than hemi-CC7. Neurotization on both supra-scapular and axillary nerves improved shoulder recovery. © 2013 The Authors. Microsurgery published by Wiley Periodicals, Inc. Microsurgery 34:91–101, 2014. PMID:23913440

Tu, Yuan-Kun; Tsai, Yi-Jung; Chang, Chih-Han; Su, Fong-Chin; Hsiao, Chih-Kun; Tan, Jacqueline Siau-Woon

2014-01-01

44

Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.  

PubMed

Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves. PMID:1960538

Bush, M S; Reid, A R; Allt, G

1991-09-01

45

Heterogeneous responses of dorsal root ganglion neurons in neuropathies induced by peripheral nerve trauma and the antiretroviral drug stavudine  

PubMed Central

Background Heterogeneity is increasingly recognized in clinical presentation of neuropathic pain (NP), but less often recognized in animal models. Neurochemical dysregulation in rodent dorsal root ganglia (DRG) is associated with peripheral nerve trauma, but poorly studied in non-traumatic NP conditions. Methods This study aimed to investigate the temporal expressions of activating transcription factor-3 (ATF-3), growth-associated protein-43 (GAP-43), neuropeptide Y (NPY) and galanin in traumatic and non-traumatic rat models of neuropathies associated with NP. Expressions of these markers were examined in the DRG at different time points following tibial nerve transection (TNT) injury and antiretroviral drug stavudine (d4T) administration using immunohistochemistry. The development of sensory gain following these insults was assessed by measuring limb withdrawal to a punctate mechanical stimulus. Results Both TNT-injured and d4T-treated rats developed hindpaw mechanical hypersensitivity. Robust expressions of ATF-3, GAP-43, NPY and galanin in both small- and large-sized L5 DRG neurons were observed in the DRG from TNT-injured rats. In contrast, d4T-treated rats did not exhibit any significant neurochemical changes in the DRG. Conclusions Taken together, the results suggest that ATF-3, GAP-43, NPY and galanin are likely indicators of nerve trauma-associated processes and not generic markers for NP. These experiments also demonstrate distinct expression patterns of neurochemical markers in the DRG and emphasize the mechanistic difference between nerve trauma and antiretroviral drug-associated NP. PMID:25070481

Boateng, EK; Novejarque, A; Pheby, T; Rice, ASC; Huang, W

2015-01-01

46

The influence of random element displacement on DOA estimates obtained with (Khatri-Rao-)root-MUSIC.  

PubMed

Although a wide range of direction of arrival (DOA) estimation algorithms has been described for a diverse range of array configurations, no specific stochastic analysis framework has been established to assess the probability density function of the error on DOA estimates due to random errors in the array geometry. Therefore, we propose a stochastic collocation method that relies on a generalized polynomial chaos expansion to connect the statistical distribution of random position errors to the resulting distribution of the DOA estimates. We apply this technique to the conventional root-MUSIC and the Khatri-Rao-root-MUSIC methods. According to Monte-Carlo simulations, this novel approach yields a speedup by a factor of more than 100 in terms of CPU-time for a one-dimensional case and by a factor of 56 for a two-dimensional case. PMID:25393783

Inghelbrecht, Veronique; Verhaevert, Jo; van Hecke, Tanja; Rogier, Hendrik

2014-01-01

47

The Influence of Random Element Displacement on DOA Estimates Obtained with (Khatri–Rao-)Root-MUSIC  

PubMed Central

Although a wide range of direction of arrival (DOA) estimation algorithms has been described for a diverse range of array configurations, no specific stochastic analysis framework has been established to assess the probability density function of the error on DOA estimates due to random errors in the array geometry. Therefore, we propose a stochastic collocation method that relies on a generalized polynomial chaos expansion to connect the statistical distribution of random position errors to the resulting distribution of the DOA estimates. We apply this technique to the conventional root-MUSIC and the Khatri-Rao-root-MUSIC methods. According to Monte-Carlo simulations, this novel approach yields a speedup by a factor of more than 100 in terms of CPU-time for a one-dimensional case and by a factor of 56 for a two-dimensional case. PMID:25393783

Inghelbrecht, Veronique; Verhaevert, Jo; van Hecke, Tanja; Rogier, Hendrik

2014-01-01

48

Effects of intrathecal anesthesia with different concentrations and doses on spinal cord, nerve roots and cerebrospinal fluid in dogs  

PubMed Central

Objective: To investigate the effects of intrathecal anesthesia with bupivacaine, levobupivacaine and ropivacaine hydrochloride at different doses on the spinal cord, nerve roots and cerebrospinal fluid (CSF) in dogs. Methods: Forty-two mongrel dogs were randomly divided into normal saline group (C; 2 ml), 0.5% (B1) and 0.75% (B2) bupivacaine hydrochloride groups (2 ml), 0.5% (L1) and 0.75% (L2) levobupivacaine hydrochloride group (2 ml), 0.5% (R1) and 0.75% (R2) ropivacaine hydrochloride group (2 ml), and drugs were intrathecally injected. Results: The contents of Ca2+ and MDA and SOD activity of the spinal cord were comparable among groups (P > 0.05). In Groups B1, L1 and R1, the neuronal cytoplasm of spinal tissues was basically normal, the majority of mitochondria and endoplasmic reticulum had complete structure, and the lamellar structure of modulated fibers was nearly normal. In Groups B2, L2 and R2, a small amount of mitochondrial vacuolar degeneration was found in the neuronal cytoplasm of spinal cord, but their structures were basically normal; the neural tissues exhibited focal mild edema, and most of the lamellar structure of modulated fibers and Schwann cells were nearly normal except for loose structure in several fibers and cells. Conclusion: When compared with 0.75% anesthetics for local anesthesia, the early adverse effects on the ultrastructure of the spinal cord and nerve root reduce after focal anesthesia with 0.5% anesthetics.

Guo, Jianrong; Lv, Na; Su, Yongjun; Liu, Yang; Zhang, Jianping; Yang, Dawei

2014-01-01

49

A literature review reveals that trials evaluating treatment of non-specific low back pain use inconsistent criteria to identify serious pathologies and nerve root involvement  

PubMed Central

Objectives The broad aim of this study was to assess the homogeneity of patients included in trials of non-specific low back pain (NSLBP). To do this, we investigated the consistency and clarity of criteria used to identify and exclude participants with serious pathologies and nerve root compromise in randomized controlled trials, investigating interventions for NSLBP. Methods We searched Medline database for randomized controlled trials of low back pain (LBP). published between 2000 and 2009. We then randomly selected and screened trials for inclusion until we had 50 eligible trials. Data were extracted on the criteria used to identify cases of serious conditions (e.g. cancer, fracture) and nerve root involvement. Results The majority of papers (35/50) explicitly excluded patients with serious pathology. However, the terminology used and examples given were highly variable. Nerve root involvement was an exclusion criterion in the majority but not all studies. The criteria used for excluding patients with nerve root involvement varied greatly between studies. The most common criteria were ‘motor, sensory or reflex changes’ (nine studies), followed by ‘pain radiating below the knee’ (five studies) and ‘reduced straight leg raise which reproduces leg pain’ (five studies). In half of the included studies, the criteria used, while alluding to nerve root involvement, were not explained adequately for us to determine the types of patients included or excluded. Discussion The inconsistent and unclear criteria used to identify cases of serious pathology and nerve root compromise means that published trials of LBP likely include heterogeneous patient populations. This trait limits our ability to make comparisons across trials or pool studies. Standardization and consensus is important for future research. PMID:23633884

Williams, Ciaran; Hancock, Mark J; Ferreira, Manuela; Ferreira, Paulo; Maher, Chris G

2012-01-01

50

Application of Pulsed Radiofrequency Currents to Rat Dorsal Root Ganglia Modulates Nerve Injury-Induced Tactile Allodynia  

PubMed Central

Background Application of pulsed radiofrequency (PRF) currents to the dorsal root ganglia (DRG) has been reported to produce relief from certain pain states without causing thermal ablation. In this study, we examined the direct correlation between PRF application to DRG associated with spinal nerve injury and reversal of injury-induced behavioral hypersensitivity in a rat neuropathic pain model. Methods Neuropathic lesioning was performed via left L5 spinal nerve ligation on male adult Sprague-Dawley rats. Once the injured rats had developed tactile allodynia, one group was then assigned to PRF treatment of the L5 DRG and another group was assigned to the sham treatment to the DRG. Behavioral testing was performed on both the control and treated paws using the von Frey filament test before the surgery and at indicated days. The resulting data were analyzed using a linear mixed model to assess the overall difference between the treatment groups and the overall difference among the study days. Cohen’s d statistic was computed from paired difference-from-baseline scores for each of the 14 study days after treatment and these measures of effect-size were then used to descriptively compare the recovery patterns over time for each study group. Results Spinal nerve injury resulted in the development of behavioral hypersensitivity to von Frey filament stimulation (allodynia) in the hindpaw of the left (injury) side. Mixed Linear modeling showed a significant difference between the treatment groups (p = 0.0079) and a significant change of paw withdrawal threshold means over time (p = 0.0006) for all 12 animals. Evaluation of Cohen’s d (effect size) revealed that the PRF-treated animals exhibited better recovery and recorded larger effect-sizes than the sham-treated animals on 10 of the 14 post-PRF treatment days and exhibited moderate to strong effects posttreatment at days 8–10 and at and beyond day 32. Conclusions Findings from this study support that PRF of the DRG causes reversal of nerve injury (spinal nerve ligation)-induced tactile allodynia in rats. This allodynia reversal indicates that nonablative PRF acting via modulation of the DRG can speed recovery in nerve injury-induced pain. PMID:21596869

Perret, Danielle M; Kim, Doo-Sik; Li, Kang-Wu; Sinavsky, Karin; Newcomb, Robert L; Miller, Jason M; Luo, Z. David

2011-01-01

51

Three-Dimensional Analysis of Nuclear Size, Shape and Displacement in Clover Root Cap Statocytes from Space and a Clinostat  

NASA Technical Reports Server (NTRS)

Under normal (l-g) conditions the statocytes of root caps have a characteristic polarity with the nucleus in tight association with the proximal cell wall; but, in altered gravity environments including microgravity (mu-g) and the clinostat (c-g) movement of the nucleus away from the proximal cell wall is not uncommon. To further understand the cause of gravity-dependent nuclear displacement in statocytes, three-dimensional cell reconstruction techniques were used to precisely measure the volumes, shapes, and positions of nuclei in white clover (Trifolium repens) flown in space and rotated on a clinostat. Seeds were germinated and grown for 72 hours aboard the Space Shuttle (STS-63) in the Fluid Processing Apparatus (BioServe Space Technologies, Univ. of Colorado, Boulder). Clinorotation experiments were performed on a two-axis clinostat (BioServe). Computer reconstruction of selected groups of statocytes were made from serial sections (0.5 microns thick) using the ROSS (Reconstruction Of Serial Sections) software package (Biocomputation Center, NASA Ames Research Center). Nuclei were significantly displaced from the tops of cells in mu-g (4.2 +/- 1.0 microns) and c-g (4.9 +/- 1.4 microns) when compared to l-g controls (3.4 +/- 0.8 gm); but, nuclear volume (113 +/- 36 cu microns, 127 +/- 32 cu microns and 125 +/- 28 cu microns for l-g, mu-g and c-g respectively) and the ratio of nuclear volume to cell volume (4.310.7%, 4.211.0% and 4.911.4% respectively) were not significantly dependent on gravity treatment (ANOVA; alpha = 0.05). Three-dimensional analysis of nuclear shape and proximity to the cell wall, however, showed that nuclei from l-g controls appeared ellipsoidal while those from space and the clinostat were more spherically shaped. This change in nuclear shape may be responsible for its displacement under altered gravity conditions. Since the cytoskeleton is known to affect nuclear polarity in root cap statocytes, those same cytoskeletal elements could also control nuclear shape. This alteration in nuclear shape and position in mu-g and c-g when compared to l-g may lead to functional differences in the gravity signaling systems of plants subjected to altered gravity environments.

Smith, J.D.; Todd, P. W.; Staehelin, L. A.; Holton, Emily (Technical Monitor)

1997-01-01

52

Intracisternal administration of NR2 subunit antagonists attenuates the nociceptive behavior and p-p38 MAPK expression produced by compression of the trigeminal nerve root  

PubMed Central

Background We investigated the role of the central NMDA receptor NR2 subunits in the modulation of nociceptive behavior and p-p38 MAPK expression in a rat model with compression of the trigeminal nerve root. To address this possibility, changes in air-puff thresholds and pin-prick scores were determined following an intracisternal administration of NR2 subunit antagonists. We also examined effects of NR2 subunit antagonists on the p-p38 MAPK expression. Results Experiments were carried out using male Sprague-Dawley rats weighing (200-230 g). Compression of the trigeminal nerve root was performed under pentobarbital sodium (40 mg/kg) anesthesia. Compression of the trigeminal nerve root produced distinct nociceptive behavior such as mechanical allodynia and hyperalgesia. Intracisternal administration of 10 or 20 ?g of D-AP5 significantly increased the air-puff threshold and decreased the pin-prick scores in a dose-dependent manner. The intracisternal administration of PPPA (1, 10 ?g), or PPDA (5, 10 ?g) increased the air-puff threshold and decreased the pin-prick scores ipsilateral as well as contralateral to the compression of the trigeminal root. Compression of the trigeminal nerve root upregulated the expression of p-p38 MAPK in the ipsilateral medullary dorsal horn which was diminished by D-AP5, PPPA, PPDA, but not Ro25-6981. Conclusions Our findings suggest that central NMDA receptor NR2 subunits play an important role in the central processing of trigeminal neuralgia-like nociception in rats with compression of the trigeminal nerve root. Our data further indicate that the targeted blockade of NR2 subunits is a potentially important new treatments strategy for trigeminal neuralgia-like nociception. PMID:21651766

2011-01-01

53

Spinal intradural cystic venous angioma originating from a nerve root in the cauda equina.  

PubMed

A spinal intradural extramedullary venous angioma is extremely rare and has not been previously reported. In this paper, the authors report on this entity with morphological and immunohistochemical evidence, and discuss the surgical strategy for its treatment. A 54-year-old woman presented to Nagoya University Hospital complaining of left-sided pain in the hip, thigh, and inguinal and perianal regions, with progressive worsening during the previous 2 weeks. Lumbar spine MRI showed an intradural extramedullary cyst at the level of T12-L1, which extended from the conus medullaris to the cauda equina. The cyst wall was not enhanced on T1-weighted MRI with Gd. Intraoperatively, a midline dural opening allowed the authors to easily visualize a dark-reddish cyst behind the spinal nerve rootlets in the cauda equina adjacent to the conus medullaris. The cyst was believed to originate from one of the spinal nerve rootlets in the cauda equina and a cluster of veins was identified on the cyst wall. The cyst was resected with the affected nerve rootlet. The surgery left no detectable neurological deficit. Based on the morphological and immunohistochemical evidence, the lesion was diagnosed as a venous angioma. No tumor recurrence was confirmed based on MRI at the time of the 2-year follow up. This is the first report of an intradural extramedullary cystic venous angioma that was successfully resected. PMID:24093468

Nishimura, Yusuke; Hara, Masahito; Natsume, Atsushi; Nakajima, Yasuhiro; Fukuyama, Ryuichi; Wakabayashi, Toshihiko; Ginsberg, Howard J

2013-12-01

54

Ultrasound guided selective cervical nerve root block and superficial cervical plexus block for surgeries on the clavicle.  

PubMed

We report the anaesthetic management of two cases involving surgeries on the clavicle, performed under superficial cervical plexus block and selective C5 nerve root block under ultrasound (US) guidance, along with general anaesthesia. Regional analgesia for clavicular surgeries is challenging. Our patients also had significant comorbidities necessitating individualised approach. The first patient had a history of emphysema, obesity, and was allergic to morphine and hydromorphone. The second patient had clavicular arthritis and pain due to previous surgeries. He had a history of smoking, Stevens-Johnson syndrome, along with daily marijuana and prescription opioid use. Both patients had an effective regional block and required minimal supplementation of analgesia, both being discharged on the same day. Interscalene block with its associated risks and complications may not be suitable for every patient. This report highlights the importance of selective regional blockade and also the use of US guidance for an effective and safe block. PMID:25024480

Shanthanna, Harsha

2014-05-01

55

Sciatic nerve injury induces apoptosis of dorsal root ganglion satellite glial cells and selectively modifies neurosteroidogenesis in sensory neurons.  

PubMed

Neurosteroids are synthesized either by glial cells, by neurons, or within the context of neuron-glia cross-talk. Various studies suggested neurosteroid involvement in the control of neurodegeneration but there is no evidence showing that the natural protection of nerve cells against apoptosis directly depends on their own capacity to produce neuroprotective neurosteroids. Here, we investigated the interactions between neurosteroidogenesis and apoptosis occurring in sensory structures of rats subjected to neuropathic pain generated by sciatic nerve chronic constriction injury (CCI). Using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), we observed no apoptotic cells in the spinal cord up to 30 days after CCI although pain symptoms such as mechano-allodynia, thermal and mechanical hyperalgesia were evidenced with the Hargreaves's behavioral and von Frey filament tests. In contrast, double-labeling experiments combining TUNEL and immunostaining with antibodies against glutamine synthetase or neuronal nuclei protein revealed apoptosis occurrence in satellite glial cells (SGC) (not in neurons) of CCI rat ipsilateral dorsal root ganglia (DRG) at day 30 after injury. Pulse-chase experiments coupled with high performance liquid chromatography and flow scintillation detection showed that, among numerous biosynthetic pathways converting [(3)H]pregnenolone into various [(3)H]neurosteroids, only [(3)H]estradiol formation was selectively modified and upregulated in DRG of CCI rats. Consistently, immunohistochemical investigations localized aromatase (estradiol-synthesizing enzyme) in DRG neurons but not in SGC. Pharmacological inhibition of aromatase caused apoptosis of CCI rat DRG neurons. Altogether, our results suggest that endogenously produced neurosteroids such as estradiol may be pivotal for the protection of DRG sensory neurons against sciatic nerve CCI-induced apoptosis. PMID:19565659

Schaeffer, Véronique; Meyer, Laurence; Patte-Mensah, Christine; Eckert, Anne; Mensah-Nyagan, Ayikoe G

2010-01-15

56

Correlation Between Vasodilatation and Secretion in the Lacrimal Gland Elicited by Stimulation of the Cornea and Facial Nerve Root of the Cat  

Microsoft Academic Search

Purpose. To determine whether reflex vasodilatation can be elicited in the cat lacrimal gland by electrical stimulation of the cornea, whether the vasodilatation elicited by electrical stimula- tion of the facial nerve root found to be the efferent arm of the cornea-lacrimal gland reflex pathway correlates with the evoked secretion in the lacrimal gland, and what kind of receptors and

Tomoki Yasui; Keishiro Karita; Hiroshi Izumi; Makoto Tamai

57

An unusual branching pattern of the superficial brachial artery accompanied by an ulnar nerve with two roots  

PubMed Central

Variations in the arterial pattern of the upper limb are common and have been reported by several investigators (Fuss et al. 1985; Poteat, 1986; Tountas & Bergman, 1993; Rodriguez-Baeza et al. 1995). These variations are often associated with anomalies in the arrangement of the nerves of the brachial plexus (Miller, 1939; Lengele & Dhem, 1989). The presence of a superficial brachial artery (Schwyzer & De Garis, 1935; Skopakoff, 1959; Fuss et al. 1985) and the usual pattern of its branching in the upper arm or forearm have also been reported (McCormack et al. 1953; Keen, 1961; Karlson & Niechalev, 1982; Lippert & Pabst, 1985; Rodriguez-Baeza et al. 1995). The great variability of this arterial pattern may be attributed to the failure of regression of some paths of the embryonic arterial trunks (Tountas & Bergman, 1993; Rodriguez-Baeza et al. 1995). The aim of the present report is to describe the concomitant appearance of 3 unusual variations in the same upper limb of a male cadaver. In this arm: (1) a superficial brachial artery terminated its course by dividing into 3 branches at the cubital fossa; (2) the definitive brachial artery had an unusual origin; and (3) the ulnar nerve was abnormally formed from 2 roots. This novel variation is compared with other anatomical variations in the arterial supply of the upper limb. In a series of routine dissections of 100 embalmed human cadavers the following variations were observed in the right upper limb of a male subject. PMID:10580863

ANAGNOSTOPOULOU, S.; VENIERATOS, D.

1999-01-01

58

Expression profile of aminoacyl-tRNA synthetases in dorsal root ganglion neurons after peripheral nerve injury.  

PubMed

Aminoacyl-tRNA synthetases (AminoARSs) are essential enzymes involved in acylating tRNA with amino acids. In addition to the typical functions of AminoARSs, various non-canonical functions have been reported, such as involvement in cellular regulatory processes and signal transduction. Here, to explore the cellular changes in sensory neurons after nerve injury, we evaluated AARS mRNA expression in rat dorsal root ganglia (DRG) neurons using AminoARS-specific primers. Of 20 AminoARSs, we found that expression of lysyl-tRNA synthetase (KARS) and glutaminyl-tRNA synthetase (QARS) was decreased in the DRG injured side. We observed decreased KARS and QARS expression in DRG neuronal cell bodies, but not in satellite cells. Therefore, we suggest the possibility that KARS and QARS may act as signaling molecules to transfer abnormal sensory signals to the spinal dorsal horn after peripheral nerve damage. Therefore, KARS and QARS may represent powerful pharmaceutical targets via control of their non-canonical functions. PMID:25467976

Park, Byung Sun; Jo, Hyun Woo; Jung, Junyang

2014-12-01

59

The effects of anticonvulsants on 4-aminopyridine-induced bursting: in vitro studies on rat peripheral nerve and dorsal roots.  

PubMed Central

1. Aminopyridines have been used as beneficial symptomatic treatments in a variety of neurological conditions including multiple sclerosis but have been associated with considerable toxicity in the form of abdominal pain, paraesthesias and (rarely) convulsions. 2. Extracellular and intracellular recording was used to characterize action potentials in rat sciatic nerves and dorsal roots and the effects of 4-aminopyridine (4-AP). 3. In sciatic nerve trunks, 1 mM 4-AP produced pronounced after potentials at room temperature secondary to regenerative firing in affected axons (5-10 spikes per stimulus). At physiological temperatures, after potentials (2-3 spikes) were greatly attenuated in peripheral axons. 4. 4-AP evoked more pronounced and prolonged after discharges in isolated dorsal roots at 37 degrees C (3-5.5 mV and 80-100 ms succeeded by a smaller inhibitory/depolarizing voltage shift) which were used to assess the effects of anticonvulsants. 5. Phenytoin, carbamazepine and lamotrigine dose-dependently reduced the area of 4-AP-induced after potentials at 100 and 320 microM but the amplitude of compound action potentials (evoked at 0.5 Hz) was depressed in parallel. 6. The tonic block of sensory action potentials by all three drugs (at 320 microM) was enhanced by high frequency stimulation (5-500 Hz). 7. The lack of selectivity of these frequency-dependent Na+ channel blockers for burst firing compared to low-frequency spikes, is discussed in contrast to their effects on 4-AP-induced seizures and paroxysmal activity in CNS tissue (which is associated with large and sustained depolarizing plateau potentials). 8. In conclusion, these in vitro results confirm the marked sensitivity of sensory axons to 4-AP (the presumptive basis for paraesthesias). Burst firing was not preferentially impaired at relatively high concentrations suggesting that anticonvulsants will not overcome the toxic peripheral actions of 4-AP in neurological patients. PMID:8821551

Lees, G.

1996-01-01

60

To replace or not to replace? - Partial coning and a sixth nerve palsy secondary due to displacement of a tunnelled intrathecal catheter for pain control.  

PubMed

We report the displacement of a tunnelled intrathecal catheter causing significant cerebrospinal fluid (CSF) leak, resulting in partial coning and a sixth nerve palsy. The patient had advanced malignant mesothelioma and all other methods of pain control had been unsuccessful. As far as we are aware, there are no published reports of early replacement of an intrathecal catheter in patients with neurological sequelae. Surgical re-siting of the intrathecal catheter produced good pain relief for many months. Doctors involved in the use of indwelling intrathecal catheters for pain control must be aware of the risk of significant neurological sequelae but should not dismiss re-establishment of intrathecal therapy in the presence of significant neurological complications. PMID:18612034

Gibbins, J; Steeds, C; Greenslade, G L; Tunstall, S R; Patel, N K; Stannard, C F

2008-07-01

61

Neurotrophic and neuroprotective actions of Achyranthes bidentata polypeptides on cultured dorsal root ganglia of rats and on crushed common peroneal nerve of rabbits.  

PubMed

We have isolated Achyranthes bidentata Blume polypeptides (ABPP) from the aqueous extract of A. bidentata Blume, a traditional Chinese medicine with multiple therapeutic applications. In this study, we aimed to investigate neurotrophic effects of ABPP on cultured dorsal root ganglia (DRGs) of rats and neuroprotective effects on crushed common peroneal nerve of rabbits. Immunochemistry and Western blot analysis indicated that ABPP (0.01, 0.1, and 1.0 ?g/ml) encouraged neurite outgrowth from cultured DRG explants/neurons in a concentration-dependent manner through activation of ERK1/2. After crush injury to rabbit common peroneal nerve, animals received daily administration of ABPP for 5 weeks. Electrophysiological assessments and histomorphological evaluation showed that 6.0mg/kg ABPP significantly enhanced nerve regeneration and function restoration. Our findings suggest that ABPP could be used as a neurotrophic and neuroprotective agent to treat peripheral nerve crush injury. PMID:24361134

Cheng, Qiong; Yuan, Ying; Sun, Changnan; Gu, Xiaosong; Cao, Zheng; Ding, Fei

2014-03-01

62

Syndrome of the cervical plexus caused by high cervical nerve root compression.  

PubMed

Lesions affecting the roots of the cervical plexus can cause a syndrome not previously described. The C3-C4 disc space is the most likely to be involved, but pressure on the C5 root can also produce facial, auricular, or retroauricular pain. Motor innervation to the diaphragm can be affected, and even the uppermost disc space at C2-C3 might be implicated. Findings on examination findings are sparse, although sensory impairment in areas of cervical plexus innervation has been observed. In a series of 1000 cervical decompression cases (both anterior and posterior) for disc disease or similar processes, only 10 instances of this syndrome have been found. Paresthesia or episodic shock-like pain affecting the ear, para-auricular, lower occipital, and mandibular areas prompted by head turning or extension are the most common complaints. PMID:2034343

Kessler, L A; Abla, A

1991-04-01

63

Dorsal root ganglion-derived Schwann cells combined with poly(lactic-co-glycolic acid)/chitosan conduits for the repair of sciatic nerve defects in rats  

PubMed Central

Schwann cells, nerve regeneration promoters in peripheral nerve tissue engineering, can be used to repair both the peripheral and central nervous systems. However, isolation and purification of Schwann cells are complicated by contamination with fibroblasts. Current reported measures are mainly limited by either high cost or complicated procedures with low cell yields or purity. In this study, we collected dorsal root ganglia from neonatal rats from which we obtained highly purified Schwann cells using serum-free melanocyte culture medium. The purity of Schwann cells (> 95%) using our method was higher than that using standard medium containing fetal bovine serum. The obtained Schwann cells were implanted into poly(lactic-co-glycolic acid)/chitosan conduits to repair 10-mm sciatic nerve defects in rats. Results showed that axonal diameter and area were significantly increased and motor functions were obviously improved in the rat sciatic nerve tissue. Experimental findings suggest that serum-free melanocyte culture medium is conducive to purify Schwann cells and poly(lactic-co-glycolic acid)/chitosan nerve conduits combined with Schwann cells contribute to restore sciatic nerve defects. PMID:25598778

Zhao, Li; Qu, Wei; Wu, Yuxuan; Ma, Hao; Jiang, Huajun

2014-01-01

64

Successful operative management of an upper lumbar spinal canal stenosis resulting in multilevel lower nerve root radiculopathy.  

PubMed

Lumbar stenosis is a common disorder, usually characterized clinically by neurogenic claudication with or without lumbar/sacral radiculopathy corresponding to the level of stenosis. We present a case of lumbar stenosis manifesting as a multilevel radiculopathy inferior to the nerve roots at the level of the stenosis. A 55-year-old gentleman presented with bilateral lower extremity pain with neurogenic claudication in an L5/S1 distribution (posterior thigh, calf, into the foot) concomitant with dorsiflexion and plantarflexion weakness. Imaging revealed grade I spondylolisthesis of L3 on L4 with severe spinal canal stenosis at L3-L4, mild left L4-L5 disc herniation, no stenosis at L5-S1, and no instability. EMG revealed active and chronic L5 and S1 radiculopathy. The patient underwent bilateral L3-L4 hemilaminotomy with left L4-L5 microdiscectomy for treatment of his L3-L4 stenosis. Postoperatively, he exhibited significant improvement in dorsiflexion and plantarflexion. The L5-S1 level was not involved in the operative decompression. Patients with radiculopathy and normal imaging at the level corresponding to the radiculopathy should not be ruled out for operative intervention should they have imaging evidence of lumbar stenosis superior to the expected affected level. PMID:25552866

McClelland, Shearwood; Kim, Stefan S

2015-01-01

65

Successful operative management of an upper lumbar spinal canal stenosis resulting in multilevel lower nerve root radiculopathy  

PubMed Central

Lumbar stenosis is a common disorder, usually characterized clinically by neurogenic claudication with or without lumbar/sacral radiculopathy corresponding to the level of stenosis. We present a case of lumbar stenosis manifesting as a multilevel radiculopathy inferior to the nerve roots at the level of the stenosis. A 55-year-old gentleman presented with bilateral lower extremity pain with neurogenic claudication in an L5/S1 distribution (posterior thigh, calf, into the foot) concomitant with dorsiflexion and plantarflexion weakness. Imaging revealed grade I spondylolisthesis of L3 on L4 with severe spinal canal stenosis at L3-L4, mild left L4-L5 disc herniation, no stenosis at L5-S1, and no instability. EMG revealed active and chronic L5 and S1 radiculopathy. The patient underwent bilateral L3-L4 hemilaminotomy with left L4-L5 microdiscectomy for treatment of his L3-L4 stenosis. Postoperatively, he exhibited significant improvement in dorsiflexion and plantarflexion. The L5-S1 level was not involved in the operative decompression. Patients with radiculopathy and normal imaging at the level corresponding to the radiculopathy should not be ruled out for operative intervention should they have imaging evidence of lumbar stenosis superior to the expected affected level. PMID:25552866

McClelland, Shearwood; Kim, Stefan S.

2015-01-01

66

Rehabilitation Considerations of a Brachial Plexus Injury with Complete Avulsion of C5 and C6 Nerve Roots in a College Football Player  

PubMed Central

Severe brachial plexus injuries are rare in sports, but they have catastrophic results with a significant loss of function in the involved upper extremity. Nerve root avulsions must be timely managed with prompt evaluation, accurate diagnosis, and surgical treatment to optimize the potential for a functional outcome. This case report describes the mechanism of injury, diagnostic evolution, surgical management, and rehabilitation of a college football player who sustained a traumatic complete nerve root avulsion of C5 and C6 (upper trunk of the brachial plexus). Diagnostics included clinical evaluation, magnetic resonance imaging, computed tomography myelogram, and electromyogram. Surgical planning included nerve grafting and neurotization (nerve transfer). Rehabilitation goals were to bring the hand to the face (active biceps function), to stabilize the shoulder for abduction and flexion, and to reduce neuropathic pain. Direct current stimulation, bracing, therapeutic exercise, and biofeedback were used to maximize the use of the athlete’s upper extremity. Although the athlete could not return to sport or normal function by most standards, his results were satisfactory in that he regained an ability to perform many activities of daily living. PMID:23015895

Saliba, Susan; Saliba, Ethan N.; Pugh, Kelli F.; Chhabra, Abhinav; Diduch, David

2009-01-01

67

Differential Effects of Electrical Stimulation of Sciatic Nerve on Metabolic Activity in Spinal Cord and Dorsal Root Ganglion in the Rat  

NASA Astrophysics Data System (ADS)

Electrical stimulation of the proximal stump of the transected sciatic nerve produces a frequency-dependent activation of glucose utilization, measured with the autoradiographic deoxy[14C]glucose method, in the dorsal horn of the spinal cord but produces no change in glucose utilization in the dorsal root ganglion cells. These results suggest that axon terminals and not the cell bodies are the sites of enhanced metabolic activity during increased functional activity of this pathway.

Kadekaro, Massako; Crane, Alison M.; Sokoloff, Louis

1985-09-01

68

Multi-scale simulations predict responses to non-invasive nerve root stimulation  

NASA Astrophysics Data System (ADS)

Objective. Established biophysical neurone models have achieved limited success in reproducing electrophysiological responses to non-invasive stimulation of the human nervous system. This is related to our insufficient knowledge of the induced electric currents inside the human body. Despite the numerous research and clinical applications of non-invasive stimulation, it is still unclear which internal sites are actually affected by it. Approach. We performed multi-scale computer simulations that, by making use of advances in computing power and numerical algorithms, combine a microscopic model of electrical excitation of neurones with a macroscopic electromagnetic model of the realistic whole-body anatomy. Main results. The simulations yield responses consistent with those experimentally recorded following magnetic and electrical motor root stimulation in human subjects, and reproduce the observed amplitudes and latencies for a wide variety of stimulation parameters. Significance. Our findings demonstrate that modern computational techniques can produce detailed predictions about which and where neurones are activated, leading to improved understanding of the physics and basic mechanisms of non-invasive stimulation and enabling potential new applications that make use of improved targeting of stimulation.

Laakso, Ilkka; Matsumoto, Hideyuki; Hirata, Akimasa; Terao, Yasuo; Hanajima, Ritsuko; Ugawa, Yoshikazu

2014-10-01

69

Computer Simulation of Nerve Transfer Strategies for Restoring Shoulder Function after Adult C5-C6 Root Avulsion Injuries  

PubMed Central

Background Functional ability following nerve transfer for upper brachial plexus injuries relies on both the function and magnitude of force recovery of targeted muscles. Following nerve transfers targeting either the axillary nerve, suprascapular nerve, or both, it is unclear whether functional ability is restored in face of limited muscle force recovery. Methods We used a computer model to simulate flexing the elbow while maintaining a functional shoulder posture for 3 nerve transfer scenarios. The minimum restored force capacity necessary to perform the task, associated compensations by neighboring muscles, and the effect of altered muscle coordination on movement effort, were assessed. Results The minimum force restored by the axillary, suprascapular, and combined nerve transfers that was required for the model to simulate the desired movement was 25%, 40%, and 15% of the unimpaired muscle force capacity, respectively. When the deltoid was paralyzed, the infraspinatus and subscapularis muscles generated higher shoulder abduction moments to compensate for deltoid weakness. For all scenarios, movement effort increased as restored force capacity decreased. Conclusions Combined axillary and suprascapular nerve transfer required the least restored force capacity to perform the desired elbow flexion task, while single suprascapular nerve transfer required the most restored force capacity to perform the same task. Though compensation mechanisms allowed all scenarios to perform the desired movement despite weakened shoulder muscles, compensation increased movement effort. Dynamic simulations allowed independent evaluation of the effect of restored force capacity on functional outcome in a way that is not possible experimentally. Clinical Relevance Simultaneous nerve transfer to suprascapular and axillary nerves yields the best simulated biomechanical outcome for lower magnitudes of muscle force recovery in this computer model. Axillary nerve transfer performs nearly as well as the combined transfer, while suprascapular nerve transfer is more sensitive to the magnitude of reinnervation and therefore avoided. PMID:21903345

Crouch, Dustin L.; Li, Zhongyu; Barnwell, Jonathan C.; Plate, Johannes F.; Daly, Melissa; Saul, Katherine R.

2011-01-01

70

The Impact of Spinal Cord Nerve Roots and Denticulate Ligaments on Cerebrospinal Fluid Dynamics in the Cervical Spine  

PubMed Central

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (?6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS. PMID:24710111

Heidari Pahlavian, Soroush; Yiallourou, Theresia; Tubbs, R. Shane; Bunck, Alexander C.; Loth, Francis; Goodin, Mark; Raisee, Mehrdad; Martin, Bryn A.

2014-01-01

71

Nerve injury induces a Gem-GTPase-dependent downregulation of P/Q-type Ca(2+) channels contributing to neurite plasticity in dorsal root ganglion neurons.  

PubMed

Small RGK GTPases, Rad, Gem, Rem1, and Rem2, are potent inhibitors of high-voltage-activated (HVA) Ca(2+) channels expressed in heterologous expression systems. However, the role of this regulation has never been clearly demonstrated in the nervous system. Using transcriptional analysis, we show that peripheral nerve injury specifically upregulates Gem in mice dorsal root ganglia. Following nerve injury, protein expression was increased in ganglia and peripheral nerve, mostly under its phosphorylated form. This was confirmed in situ and in vitro in dorsal root ganglia sensory neurons. Knockdown of endogenous Gem, using specific small-interfering RNA (siRNA), increased the HVA Ca(2+) current only in the large-somatic-sized neurons. Combining pharmacological analysis of the HVA Ca(2+) currents together with Gem siRNA-transfection of larger sensory neurons, we demonstrate that only the P/Q-type Ca(2+) channels were enhanced. In vitro analysis of Gem affinity to various CaV?x-CaV2.x complexes and immunocytochemical studies of Gem and CaV? expression in sensory neurons suggest that the specific inhibition of the P/Q channels relies on both the regionalized upregulation of Gem and the higher sensitivity of the endogenous CaV2.1-CaV?4 pair in a subset of sensory neurons including the proprioceptors. Finally, pharmacological inhibition of P/Q-type Ca(2+) current reduces neurite branching of regenerating axotomized neurons. Taken together, the present results indicate that a Gem-dependent P/Q-type Ca(2+) current inhibition may contribute to general homeostatic mechanisms following a peripheral nerve injury. PMID:24809506

Scamps, Frédérique; Sangari, Sina; Bowerman, Melissa; Rousset, Mathieu; Bellis, Michel; Cens, Thierry; Charnet, Pierre

2015-02-01

72

Electromechanical Nerve Stimulator  

NASA Technical Reports Server (NTRS)

Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

1993-01-01

73

Virus-mediated shRNA Knockdown of Nav1.3 in Rat Dorsal Root Ganglion Attenuates Nerve Injury-induced Neuropathic Pain  

PubMed Central

Neuropathic pain is a chronic condition that is often refractory to treatment with available therapies and thus an unmet medical need. We have previously shown that the voltage-gated sodium channel Nav1.3 is upregulated in peripheral and central nervous system (CNS) of rats following nerve injury, and that it contributes to nociceptive neuron hyperexcitability in neuropathic conditions. To evaluate the therapeutic potential of peripheral Nav1.3 knockdown at a specific segmental level, we constructed adeno-associated viral (AAV) vector expressing small hairpin RNA against rat Nav1.3 and injected it into lumbar dorsal root ganglion (DRG) of rats with spared nerve injury (SNI). Our data show that direct DRG injection provides a model that can be used for proof-of-principle studies in chronic pain with respect to peripheral delivery route of gene transfer constructs, high transduction efficiency, flexibility in terms of segmental localization, and limited behavioral effects of the surgical procedure. We show that knockdown of Nav1.3 in lumbar 4 (L4) DRG results in an attenuation of nerve injury-induced mechanical allodynia in the SNI model. Taken together, our studies support the contribution of peripheral Nav1.3 to pain in adult rats with neuropathic pain, validate Nav1.3 as a target, and provide validation for this approach of AAV-mediated peripheral gene therapy. PMID:22910296

Samad, Omar A; Tan, Andrew M; Cheng, Xiaoyang; Foster, Edmund; Dib-Hajj, Sulayman D; Waxman, Stephen G

2013-01-01

74

miR-21 and miR-222 inhibit apoptosis of adult dorsal root ganglion neurons by repressing TIMP3 following sciatic nerve injury.  

PubMed

MicroRNAs (miRNAs or miRs) are involved in phenotype modulation of neural cells after peripheral nerve injury. The effects of miRNAs on the survival of dorsal root ganglion (DRG) neurons, however, have not yet been well understood. In this study, microarray profiling indicated that 13 miRNAs were differentially expressed in rat DRGs (L4-L6) during the initial 7d period post sciatic nerve transection, and that the expressions of miR-21 and miR-222 (2 out of the 13 miRNAs) were continually increased over the time period. Tissue inhibitor of metalloproteinase 3 (TIMP3), a pro-apoptotic protein in various cancer cells, was identified as a common target of miR-21 and miR-222. Over-expression of miR-21 and miR-222 inhibited cell apoptosis and enhanced cell viability in cultured DRG neurons. IL-6 could induce up-regulation of miR-21 expression. All the results showed that miR-21 and miR-222 inhibited neuronal apoptosis at least partially through suppressing TIMP3 after peripheral nerve injury. PMID:25484256

Zhou, Songlin; Zhang, Shibo; Wang, Yaxian; Yi, Sheng; Zhao, Lili; Tang, Xiaoyan; Yu, Bin; Gu, Xiaosong; Ding, Fei

2015-01-23

75

Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury.  

PubMed

Neuronal calcium (Ca(2+))-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca(2+)-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca(2+)-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca(2+)-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord. PMID:24616509

Zhang, Ming-Dong; Tortoriello, Giuseppe; Hsueh, Brian; Tomer, Raju; Ye, Li; Mitsios, Nicholas; Borgius, Lotta; Grant, Gunnar; Kiehn, Ole; Watanabe, Masahiko; Uhlén, Mathias; Mulder, Jan; Deisseroth, Karl; Harkany, Tibor; Hökfelt, Tomas G M

2014-03-25

76

Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury  

PubMed Central

Neuronal calcium (Ca2+)-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca2+-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca2+-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca2+-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord. PMID:24616509

Zhang, Ming-Dong; Tortoriello, Giuseppe; Hsueh, Brian; Tomer, Raju; Ye, Li; Mitsios, Nicholas; Borgius, Lotta; Grant, Gunnar; Kiehn, Ole; Watanabe, Masahiko; Uhlén, Mathias; Mulder, Jan; Deisseroth, Karl; Harkany, Tibor; Hökfelt, Tomas G. M.

2014-01-01

77

Transient early expression of TNF-alpha in sciatic nerve and dorsal root ganglia in a mouse model of painful peripheral neuropathy.  

PubMed

The proinflammatory cytokine tumor necrosis factor-alpha (TNF) is an important mediator in neuropathic pain. We investigated the temporal pattern of TNF mRNA expression in the sciatic nerve, in dorsal root ganglia (DRG) and spinal cord in the mouse chronic constriction injury model of neuropathy with quantitative real-time polymerase chain reaction. Neuropathic pain-like behaviour was monitored by evaluating thermal hyperalgesia and mechanical allodynia. Pain-related behaviour and TNF expression were evaluated 6 h, 1, 3, 7 and 14 days after injury. Naive animals and sham-operated mice were used as controls. We found an early upregulation of sciatic nerve TNF mRNA levels in chronic constriction injury (CCI) and sham-operated animals 6 h after surgery: 1 day later TNF overexpression was present in CCI mice only and disappeared 3 days after injury. The mRNA cytokine levels were elevated in DRG 1 and 3 days after surgery in CCI animals only, while the cytokine was not modulated in the spinal cord. A significant hyperalgesia was present in CCI and sham-operated mice at 6 h and 1 day, while at later time point only CCI mice presented lower thresholds. Mechanical allodynia was already present only in CCI animals 6 h from surgery and remained constant up to the 14 th day. The results indicate that a transient early TNF upregulation takes place in peripheral nervous system after CCI that can activate a cascade of proinflammatory/pronociceptive mediators. PMID:18394803

Sacerdote, Paola; Franchi, Silvia; Trovato, Anna Elisa; Valsecchi, Anna Elisa; Panerai, Alberto E; Colleoni, Mariapia

2008-05-01

78

n5-STZ Diabetic Model Develops Alterations in Sciatic Nerve and Dorsal Root Ganglia Neurons of Wistar Rats  

PubMed Central

One experimental model of diabetes mellitus (DM) similar to type II DM, called n5-STZ, is obtained by a single injection (via i.p.) of streptozotocin (STZ) in the 5th day of life of newborn rats. The present investigation aimed to characterize alterations in excitability of rat peripheral neurons in n5-STZ model. n5-STZ DM was induced, and electrophysiological evaluation was done at 12th week of rat life. Rats developed glucose intolerance, sensory alteration, and hyperglycemia or near-normoglycemia (21.2 ± 1.6 and 7.4 ± 0.4?mmol/L). In near-normoglycemia group the significant electrophysiological alteration observed was decreased in amplitude of 2nd wave (2nd component, conduction velocity: 48.8?m/s) of compound action potential (CAP) of sciatic nerve. For hyperglycemic rats, decreased excitability, amplitude, and conduction velocity of 2nd CAP component of sciatic nerve were found; a depolarization of resting potential (4-5?mV) and reduction in maximum ascendant and descendant inclinations of action potential were found in DRG neurons but no alteration on Na+ current (INa+). Thus, n5-STZ rats develop alterations in excitability which were related to glycemic levels but were not likely attributable to changes on INa+. Our data confirm that n5-STZ model is a useful model to study type II DM. PMID:23476801

da Silva-Alves, Kerly Shamyra; Lemos-dos-Santos, Matheus; de Oliveira, Keciany Alves; Joca, Humberto Cavalcante; do Vale, Otoni Cardoso; Coelho-de-Souza, Andrelina Noronha; Leal-Cardoso, José Henrique

2013-01-01

79

Multiple schwannomas of the sciatic nerve  

Microsoft Academic Search

Schwannomas are rare benign tumours of nerve sheath cells of neural crest origin. Often these tumours are solitary and encapsulated. Multiple schwannomas can arise from the peripheral nervous system including cranial nerves, spinal roots, the brachial and lumbar–sacral plexus or major peripheral nerves. We report an extremely rare case of schwannomatosis of the sciatic nerve in a young female and

J. Huang; R. Mobbs; C. Teo

2003-01-01

80

Extracellular Nm23H1 stimulates neurite outgrowth from dorsal root ganglia neurons in vitro independently of nerve growth factor supplementation or its nucleoside diphosphate kinase activity  

SciTech Connect

Research highlights: {yields} Extracellular Nm23H1 stimulates nerve growth. {yields} Extracellular Nm23H1 provides pathfinding cues to growth cones. {yields} The neurotrophic activity of Nm23H1 is independent of NDP kinase activity. {yields} The neurotrophic activity of Nm23H1 is independent of NGF. -- Abstract: The nucleoside diphosphate (NDP) kinase, Nm23H1, is a highly expressed during neuronal development, whilst induced over-expression in neuronal cells results in increased neurite outgrowth. Extracellular Nm23H1 affects the survival, proliferation and differentiation of non-neuronal cells. Therefore, this study has examined whether extracellular Nm23H1 regulates nerve growth. We have immobilised recombinant Nm23H1 proteins to defined locations of culture plates, which were then seeded with explants of embryonic chick dorsal root ganglia (DRG) or dissociated adult rat DRG neurons. The substratum-bound extracellular Nm23H1 was stimulatory for neurite outgrowth from chick DRG explants in a concentration-dependent manner. On high concentrations of Nm23H1, chick DRG neurite outgrowth was extensive and effectively limited to the location of the Nm23H1, i.e. neuronal growth cones turned away from adjacent collagen-coated substrata. Nm23H1-coated substrata also significantly enhanced rat DRG neuronal cell adhesion and neurite outgrowth in comparison to collagen-coated substrata. These effects were independent of NGF supplementation. Recombinant Nm23H1 (H118F), which does not possess NDP kinase activity, exhibited the same activity as the wild-type protein. Hence, a novel neuro-stimulatory activity for extracellular Nm23H1 has been identified in vitro, which may function in developing neuronal systems.

Wright, K.T. [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom)] [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom); Seabright, R.; Logan, A. [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom)] [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom); Lilly, A.J.; Khanim, F.; Bunce, C.M. [Biosciences, Birmingham University, Birmingham (United Kingdom)] [Biosciences, Birmingham University, Birmingham (United Kingdom); Johnson, W.E.B., E-mail: w.e.johnson@aston.ac.uk [Life and Health Sciences, Aston University, Birmingham (United Kingdom)] [Life and Health Sciences, Aston University, Birmingham (United Kingdom)

2010-07-16

81

Subtype-specific reduction of Voltage-gated Calcium Current in Medium-Sized Dorsal Root Ganglion Neurons after Painful Peripheral Nerve Injury  

PubMed Central

Sensory neurons express a variety of voltage-gated Ca2+ channel subtypes, but reports differ on their proportionate representation, and the effects of painful nerve injury on each subtype are not established. We compared levels of high-voltage activated currents in medium-sized (30-40?m) dorsal root ganglion neurons dissociated from control animals and those subjected to spinal nerve ligation, using sequential application of semiselective channel blockers (nisoldipine for L-type, SNX-111 or ?-conotoxin GVIA for N-type, agatoxin IVA or ?-Conotoxin MVIIC for P/Q-type, and SNX-482 for a component of R-type) during either square wave depolarizations or action potential waveform voltage commands. Using sequential administration of multiple blockers, proportions of total Ca2+ current attributable to different subtypes and the effect of injury depended on the sequence of blocker administration and type of depolarization command. Overall, however, N-type and L-type currents comprised the dominant components of ICa in sensory neurons under control conditions, and these subtypes showed the greatest loss of current following injury (L-type 26-71% loss, N-type 0-51% loss). Further exploration of N-type current identified by its sensitivity to ?-conotoxin GVIA applied alone showed that injury reduced the peak N-type current during step depolarization by 68% and decreased the total charge entry during action potential waveform stimulation by 44%. Isolation of N-type current by blockade of all other subtypes demonstrated a 50% loss with injury, and also revealed an injury-related rightward shift in the activation curve. Nonstationary noise analyses of N-type current in injured neurons revealed unitary channel current and number of channels that were not different from control, which indicates that injury-induced loss of current is due to a decrease in channel open probability. Our findings suggest that diminished Ca2+ influx through N-type and L-type channels may contribute to sensory neuron dysfunction and pain after nerve injury. PMID:21277351

McCallum, J. Bruce; Wu, Hsiang-En; Tang, Qingbo; Kwok, Wai-Meng; Hogan, Quinn H.

2011-01-01

82

De novo expression of Nav1.7 in injured putative proprioceptive afferents: Multiple tetrodotoxin-sensitive sodium channels are retained in the rat dorsal root after spinal nerve ligation.  

PubMed

Tetrodotoxin-sensitive (TTX-s) spontaneous activity is recorded from the dorsal roots after peripheral nerve injury. Primary sensory neurons in the dorsal root ganglion (DRG) express multiple TTX-s voltage-gated sodium channel ?-subunits (Navs). Since Nav1.3 increases, whereas all other Navs decrease, in the DRG neurons after peripheral nerve lesion, Nav1.3 is proposed to be critical for the generation of these spontaneous discharges and the contributions of other Navs have been ignored. Here, we re-evaluate the changes in expression of three other TTX-s Navs, Nav1.1, Nav1.6 and Nav1.7, in the injured 5th lumbar (L5) primary afferent components following L5 spinal nerve ligation (SNL) using in situ hybridization histochemistry and immunohistochemistry. While the overall signal intensities for these Nav mRNAs decreased, many injured DRG neurons still expressed these transcripts at clearly detectable levels. All these Nav proteins accumulated at the proximal stump of the ligated L5 spinal nerve. The immunostaining patterns of Nav1.6 and Nav1.7 associated with the nodes of Ranvier were maintained in the ipsilateral L5 dorsal root. Interestingly, putative proprioceptive neurons characterized by ?3 Na(+)/K(+) ATPase-immunostaining specifically lacked Nav1.7 mRNA in naïve DRG but displayed de novo expression of this transcript following SNL. Nav1.7-immunoreactive fibers were significantly increased in the ipsilateral gracile nucleus where central axonal branches of the injured A-fiber afferents terminated. These data indicate that multiple TTX-s channel subunits could contribute to the generation and propagation of the spontaneous discharges in the injured primary afferents. Specifically, Nav1.7 may cause some functional changes in sensory processing in the gracile nucleus after peripheral nerve injury. PMID:25453779

Fukuoka, T; Miyoshi, K; Noguchi, K

2015-01-22

83

Multiple schwannomas of the sciatic nerve.  

PubMed

Schwannomas are rare benign tumours of nerve sheath cells of neural crest origin. Often these tumours are solitary and encapsulated. Multiple schwannomas can arise from the peripheral nervous system including cranial nerves, spinal roots, the brachial and lumbar-sacral plexus or major peripheral nerves. We report an extremely rare case of schwannomatosis of the sciatic nerve in a young female and include a comprehensive literature review. Treatment options are discussed. PMID:12763357

Huang, J; Mobbs, R; Teo, C

2003-05-01

84

Nerve blocks in the treatment of headache.  

PubMed

Nerve blocks and neurostimulation are reasonable therapeutic options in patients with head and neck neuralgias. In addition, these peripheral nerve procedures can also be effective in primary headache disorders, such as migraine and cluster headaches. Nerve blocks for headaches are generally accomplished by using small subcutaneous injections of amide-type local anesthetics, such as lidocaine and bupivicaine. Targets include the greater occipital nerve, lesser occipital nerve, auriculotemporal nerve, supratrochlear and supraorbital nerves, sphenopalatine ganglion, cervical spinal roots, and facet joints of the upper cervical spine. Although definitive studies examining the usefulness of nerve blocks are lacking, reports suggest that this area deserves further attention in the hope of acquiring evidence of effectiveness. PMID:20430319

Levin, Morris

2010-04-01

85

Nerve lesions and the generation of pain  

Microsoft Academic Search

This review addresses the issue of how axotomy of periph- eral nerve fibers leads to pain and hyperalgesia. The point of axotomy (the nerve injury site), the dorsal root ganglia, and the dorsal horn of the spinal cord are candidate sites for generation of the pain signal that is likely to be critical for maintaining the neuropathic pain state. This

James N. Campbell

2001-01-01

86

Changes in Expression of Two Tetrodotoxin-Resistant Sodium Channels and Their Currents in Dorsal Root Ganglion Neurons after Sciatic Nerve Injury But Not Rhizotomy  

Microsoft Academic Search

Two TTX-resistant sodium channels, SNS and NaN, are prefer- entially expressed in c-type dorsal root ganglion (DRG) neurons and have been shown recently to have distinct electrophysiolog- ical signatures, SNS producing a slowly inactivating and NaN producing a persistent sodium current with a relatively hyperpo- larized voltage-dependence. An attenuation of SNS and NaN transcripts has been demonstrated in small DRG

Amanda A. Sleeper; Theodore R. Cummins; Sulayman D. Dib-Hajj; William Hormuzdiar; Lynda Tyrrell; Stephen G. Waxman; Joel A. Black

2000-01-01

87

Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.  

PubMed

Fibre structures represent a potential class of materials for the formation of synthetic nerve conduits due to their biomimicking architecture. Although the advantages of fibres in enhancing nerve regeneration have been demonstrated, in vivo evaluation of fibre size effect on nerve regeneration remains limited. In this study, we analyzed the effects of fibre diameter of electrospun conduits on peripheral nerve regeneration across a 15-mm critical defect gap in a rat sciatic nerve injury model. By using an electrospinning technique, fibrous conduits comprised of aligned electrospun poly (?-caprolactone) (PCL) microfibers (981?±?83 nm, Microfiber) or nanofibers (251?±?32 nm, Nanofiber) were obtained. At three months post implantation, axons regenerated across the defect gap in all animals that received fibrous conduits. In contrast, complete nerve regeneration was not observed in the control group that received empty, non-porous PCL film conduits (Film). Nanofiber conduits resulted in significantly higher total number of myelinated axons and thicker myelin sheaths compared to Microfiber and Film conduits. Retrograde labeling revealed a significant increase in number of regenerated dorsal root ganglion sensory neurons in the presence of Nanofiber conduits (1.93 ± 0.71 × 10(3) vs. 0.98 ± 0.30 × 10(3) in Microfiber, p?nerve regeneration. These results could provide useful insights for future nerve guide designs. PMID:22700359

Jiang, Xu; Mi, Ruifa; Hoke, Ahmet; Chew, Sing Yian

2014-05-01

88

Computer Simulation of Antidromic Facial Nerve Response Waveform  

Microsoft Academic Search

Conclusion: An assessment of facial nerve (FN) damage on the basis of antidromic facial nerve response (AFNR) was established by computer simulation analysis. Computer simulation has the advantage of being able to assume any type of lesion. In the near future, computer analysis should provide another experimental method which displaces animal experiments, thus circumventing the ethical dilemma associated with animal

Mitsuru Iwai; Taizo Takeda; Hiroaki Nakatani; Akinobu Kakigi

2009-01-01

89

Lateral displacement and rotational displacement sensor  

DOEpatents

A position measuring sensor formed from opposing sets of capacitor plates measures both rotational displacement and lateral displacement from the changes in capacitances as overlapping areas of capacitors change. Capacitances are measured by a measuring circuit. The measured capacitances are provided to a calculating circuit that performs calculations to obtain angular and lateral displacement from the capacitances measured by the measuring circuit.

Duden, Thomas

2014-04-22

90

Intermediate nerve neuralgia can be diagnosed and cured by microvascular decompression.  

PubMed

Here, we present a case of a 55-year-old woman with a 10-year history of hemifacial spasm accompanied by 1-month ipsilateral paroxysmal otalgia. Magnetic resonance imaging revealed the presence of vessels around the facial nerve root. Surgical exploration via suboccipital retromastoid craniotomy showed converging compression of the facial nerve root and intermediate nerve from both sides by an anterior inferior cerebellar artery loop. The patient's hemifacial spasm and ipsilateral otalgia were completely relieved after microvascular decompression of the facial nerve root and intermediate nerve. Intraoperative findings and the postoperative result of this case confirmed that vascular compression of the intermediate nerve was the exclusive cause of paroxysmal otalgia. The presence of ipsilateral hemifacial spasm, combined with preoperative neuroimaging studies, contributed to the diagnosis of intermediate nerve neuralgia. Microvascular decompression should be considered for the management of patients with intermediate nerve neuralgia. PMID:25006894

Chen, Yili; Song, Zhengfei; Wan, Yingfeng; Lin, Wei; Hu, Xingyue; Wang, Yirong; Imai, Hideaki

2014-07-01

91

Trigeminal impingement syndrome: the relationship between atypical trigeminal symptoms and anteromedial disk displacement.  

PubMed

The purpose of this study was to determine if compression of the mandibular nerve and its branches could be caused by antero-medial disk displacement, resulting in atypical facial pain. Sixteen temporomandibular joints (TMJ) were dissected and injected with an autopolymerizing solution into the superior compartment, which produced an artificial capsular swelling that caused disk displacement. In all specimens, the TMJ capsule was close to the mandibular branch of the trigeminal nerve after the intracapsular injection. Thus, capsular distension or antero-medial disk displacement, as seen in various temporomandibular disorders (TMD), could result in nerve compression and facial pain symptoms. PMID:20806735

Cascone, Piero; Fatone, Flavia Maria Graziana; Paparo, Francesco; Arangio, Paolo; Iannetti, Giorgio

2010-07-01

92

Nerve Impulses in Plants  

ERIC Educational Resources Information Center

Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

Blatt, F. J.

1974-01-01

93

Fibrolipomatous hamartoma of nerve.  

PubMed

Fibrolipomatous hamartomas of nerve are rare, benign, fibrofatty malformations of peripheral nerves, most commonly affecting the median nerve. Lower extremity cases are extremely rare. The authors present a very rare case of a fibrolipomatous hamartoma involving the superficial peroneal nerve, and review the literature regarding its clinical presentation and surgical management. PMID:8161996

Bibbo, C; Warren, A M

1994-01-01

94

Fiber composition of the rat sciatic nerve.  

PubMed

The rat sciatic nerve originates from the spinal segments L4-L6. It is unifascicular at the trochanter; 5-7 mm distally, the nerve splits into two and then into four fascicles. The tibial portion gives rise to the tibial and the sural nerves, and the peroneal portion gives rise to the peroneal nerve and a cutaneous branch that perforates the lateral hamstring muscles to innervate the proximolateral face of the calf. The number and type of the axons in these branches were determined in light and electron micrographs of normal nerves, and after de-efferentation or sympathectomy. Deafferentation was technically not feasible because spinal ganglia and ventral roots were supplied by the same vascular plexus. The tibial nerve contained 1,000 motor and 3,500 myelinated afferent axons, 3,700 sympathetic axons, and 5,400 unmyelinated afferent axons. The peroneal nerve contained 600 motor and 1,300 myelinated afferent axons, 1,100 sympathetic axons and 3,000 unmyelinated afferent axons. The sural nerve contained 1,100 myelinated and 2,800 unmyelinated afferent axons; in addition, there were 1,500 unmyelinated sympathetic axons. The cutaneous branch consisted of 400 myelinated and 1,800 unmyelinated afferent axons. Thus, the entire sciatic nerve at midthigh is composed of about 27,000 axons; 6% are myelinated motor axons, 23% and 48% are myelinated and unmyelinated sensory axons, respectively, and 23% are unmyelinated sympathetic axons. The techniques used did not demonstrate sympathetic axons in the cutaneous branch and did not reveal the few motor axons contained in the sural nerve. PMID:3706794

Schmalbruch, H

1986-05-01

95

Nerve injuries about the elbow in the athlete.  

PubMed

The athlete's elbow is a remarkable example of motion, strength, and durability. The stress placed on the elbow during sport, including the throwing motion, may lead to soft-tissue ligamentous and nerve injury. The thrower's elbow illustrates one example of possible nerve injury about the elbow in sport, related to chronic repetitive tensile and compressive stresses to the ulnar nerve associated with elbow flexion and valgus position. Besides the throwing athlete, nerve injury from high-energy direct-impact forces may also damage nerves around the elbow in contact sports. Detailed history and physical examination can often make the diagnosis of most upper extremity neuropathies. The clinician must be aware of the possibility of isolated or combined nerve injury as far proximal as the cervical nerve roots, through the brachial plexus, to the peripheral nerve terminal branches. Electrodiagnostic studies are occasionally beneficial for diagnosis with certain nerves. Nonoperative management is often successful in most elbow and upper extremity neuropathies. If conservative treatment fails, then surgical treatment should address all potentially offending structures. In the presence of medial laxity and concurrent ulnar neuritis, the medial ulnar collateral ligament warrants surgical treatment, in addition to transposition of the ulnar nerve. The morbidity of open surgical decompression of nerves in and around the elbow is potentially career threatening in the throwing athlete. This mandates an assessment of the adequacy of the nonsurgical treatment and a thorough preoperative discussion of the risks and benefits of surgery. PMID:25077754

Harris, Joshua D; Lintner, David M

2014-09-01

96

Thoracic splanchnic nerves: implications for splanchnic denervation  

PubMed Central

Splanchnic neurectomy is of value in the management of chronic abdominal pain. It is postulated that the inconsistent results of splanchnicectomies may be due to anatomical variations in the pattern of splanchnic nerves. The advent of minimally invasive and video-assisted surgery has rekindled interest in the frequency of variations of the splanchnic nerves. The aims of this study were to investigate the incidence, origin and pattern of the splanchnic nerves in order to establish a predictable pattern of splanchnic neural anatomy that may be of surgical relevance. Six adult and 14 fetal cadavers were dissected (n = 38). The origin of the splanchnic nerve was bilaterally asymmetrical in all cases. The greater splanchnic nerve (GSN) was always present, whereas the lesser splanchnic nerve (LSN) and least splanchnic nerve (lSN) were inconsistent (LSN, 35 of 38 sides (92%); LSN, 21 of 38 sides (55%). The splanchnic nerves were observed most frequently over the following ranges: GSN, T6–9: 28 of 38 sides (73%); LSN, when present, T10–11: (10 of 35 sides (29%); and lSN, T11–12: 3 of 21 sides (14%). The number of ganglionic roots of the GSN varied between 3 and 10 (widest T4–11; narrowest, T5–7). Intermediate splanchnic ganglia, when present, were observed only on the GSN main trunk with an incidence of 6 of 10 sides (60%) in the adult and 11 of 28 sides (39%) in the fetus. The higher incidence of the origin of GSN above T5 has clinical implications, given the widely discussed technique of undertaking splanchnicectomy from the T5 ganglion distally. This approach overlooks important nerve contributions and thereby may compromise clinical outcome. In the light of these variations, a reappraisal of current surgical techniques used in thoracoscopic splanchnicectomy is warranted. PMID:11760889

NAIDOO, N.; PARTAB, P.; PATHER, N.; MOODLEY, J.; SINGH, B.; SATYAPAL, K. S.

2001-01-01

97

Abducens nerve palsy after schwannoma resection.  

PubMed

Tumors of the posterior mediastinum are mostly neurogenic and could involve the intervertebral foramen and the medullary canal. We describe the case of a patient who underwent surgery for a nerve sheet tumor originating at the level of the right second neural root. Resection was associated with an incidental dural tear and cerebrospinal fluid leak that was promptly repaired. One week after surgery, horizontal diplopia occurred. A palsy of the left abducens nerve secondary to intracranial hypotension was diagnosed. We present the pathogenic cascade leading to this ocular complication after posterior mediastinal surgery. The surgical techniques to prevent this complication are discussed. PMID:25639411

Bobbio, Antonio; Hamelin-Canny, Emelyne; Roche, Nicolas; Taillia, Herve; Alifano, Marco

2015-02-01

98

Nerve conduction velocity  

MedlinePLUS

... to determine the speed of the nerve signals. Electromyography (recording from needles placed into the muscles) is ... Often, the nerve conduction test is followed by electromyography (EMG). In this test, needles are placed into ...

99

Precision displacement reference system  

DOEpatents

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)

2000-02-22

100

Root systems  

NSDL National Science Digital Library

One purpose that roots serve is that of anchoring the plant in the ground. Roots also take up water and nutrients for the plant. Plants all have different root system types to fit their individual needs and locations.

N/A N/A (U.S. Government;)

2004-10-30

101

Chromo-fluorogenic BODIPY-complexes for selective detection of V-type nerve agent surrogates.  

PubMed

Two new Eu(3+) and Au(3+) BODIPY-complexes capable of chromo-fluorogenically detecting micromolar concentrations of V-type nerve agent surrogates by a simple displacement assay are described. PMID:25233370

Barba-Bon, Andrea; Costero, Ana María; Gil, Salvador; Sancenón, Félix; Martínez-Máñez, Ramón

2014-11-11

102

Joint estimation of real squeezing and displacement  

E-print Network

We study the problem of joint estimation of real squeezing and amplitude of the radiation field, deriving the measurement that maximizes the probability density of detecting the true value of the unknown parameters. More generally, we provide a solution for the problem of estimating the unknown unitary action of a nonunimodular group in the maximum likelihood approach. Remarkably, in this case the optimal measurements do not coincide with the so called square-root measurements. In the case of squeezing and displacement we analyze in detail the sensitivity of estimation for coherent states and displaced squeezed states, deriving the asymptotic relation between the uncertainties in the joint estimation and the corresponding uncertainties in the optimal separate measurements of squeezing and displacement. A two-mode setup is also analyzed, showing how entanglement between optical modes can be used to approximate perfect estimation.

G. Chiribella; G. M. D'Ariano; M. F. Sacchi

2005-11-21

103

Internal Displacement Monitoring Centre  

NSDL National Science Digital Library

The Internal Displacement Monitoring Centre (IDMC) was established twelve years ago in the hope that they would "raise awareness of the plight of internally displaced people (IDP), point to gaps in national and international responses and promote solutions reflecting international standards and best practices." The Centre also keeps a database of 50 countries in which people have been displaced within their own country due to conflicts or human rights violations. To get a sense of where displaced persons are and how many countries have IDPs, visitors can click on the small world map on the far right hand side of the homepage. Scrolling over the map will reveal the number of displaced people by continent. Visitors interested in learning about an individual country can click on the continent, then click on one of the countries for an "Internal Displacement Profile", "Country Statistics", and an "Overview". The Resources tab, at the top of any page, includes "IDMC Publications", "Picture Galleries" of internally displaced people in India, Cyprus, and the West Bank, to name a few, and "IDP Maps" which has dozens of maps of from 2001 to 2009.

104

Sliding Capacitive Displacement Transducer  

NASA Technical Reports Server (NTRS)

Simple circuit replaces bridge circuit. Sliding capacitive displacement transducer, capacitance varies linearly with displacement, enables use of simple circuit based on operational amplifier instead of complicated capacitance bridge. With new circuit, transducers as small as 0.05 in. (1.3 mm) square and 0.004 in. (0.1 mm) thick have produced output-voltage changes of about 200 mV per 0.005 in. (0.13 mm) of displacement. Piston-type transducer made quite small for installation in confined spaces.

Bryner, B. D.; Godfrey, A. L.

1987-01-01

105

The furcal nerve revisited.  

PubMed

Atypical sciatica and discrepancy between clinical presentation and imaging findings is a dilemma for treating surgeon in management of lumbar disc herniation. It also constitutes ground for failed back surgery and potential litigations thereof. Furcal nerve (Furcal = forked) is an independent nerve with its own ventral and dorsal branches (rootlets) and forms a link nerve that connects lumbar and sacral plexus. Its fibers branch out to be part of femoral and obturator nerves in-addition to the lumbosacral trunk. It is most commonly found at L4 level and is the most common cause of atypical presentation of radiculopathy/sciatica. Very little is published about the furcal nerve and many are unaware of its existence. This article summarizes all the existing evidence about furcal nerve in English literature in an attempt to create awareness and offer insight about this unique entity to fellow colleagues/professionals involved in spine care. PMID:25317309

Harshavardhana, Nanjundappa S; Dabke, Harshad V

2014-08-01

106

Optical stimulation of peripheral nerves in vivo  

NASA Astrophysics Data System (ADS)

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Wells, Jonathon D.

107

Peripheral nerve regeneration and neurotrophic factors  

PubMed Central

The role of neurotrophic factors in the maintenance and survival of peripheral neuronal cells has been the subject of numerous studies. Administration of exogenous neurotrophic factors after nerve injury has been shown to mimic the effect of target organ-derived trophic factors on neuronal cells. After axotomy and during peripheral nerve regeneration, the neurotrophins NGF, NT-3 and BDNF show a well defined and selective beneficial effect on the survival and phenotypic expression of primary sensory neurons in dorsal root ganglia and of motoneurons in spinal cord. Other neurotrophic factors such as CNTF, GDNF and LIF also exert a variety of actions on neuronal cells, which appear to overlap and complement those of the neurotrophins. In addition, there is an indirect contribution of GGF to nerve regeneration. GGF is produced by neurons and stimulates proliferation of Schwann cells, underlining the close interaction between neuronal and glial cells during peripheral nerve regeneration. Different possibilities have been investigated for the delivery of growth factors to the injured neurons, in search of a suitable system for clinical applications. The studies reviewed in this article show the therapeutic potential of neurotrophic factors for the treatment of peripheral nerve injury and for neuropathies. PMID:10227662

TERENGHI, GIORGIO

1999-01-01

108

Nerve and Blood Vessels  

Microsoft Academic Search

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated\\u000a and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based\\u000a on the fascicular

Maura Valle; Maria Pia Zamorani

109

[Ultrasonographic evaluation of the sciatic nerve and thigh trauma].  

PubMed

This study was aimed at studying the normal morphology of the main extrapelvic trunk of the sciatic nerve, its average size and its anatomo-topographic relationships by means of high resolution US. The involvement of the sciatic nerve in traumas was also investigated. The lower gluteal region and the posterior aspect of both thighs were examined in 30 healthy subjects and in 11 patients with recent or previous traumas. The sciatic nerve is clearly demonstrated, on US images, between the biceps femoris muscle and the semimembranosus and semitendinosus muscles. The average dorsoventral diameter of the nerve is 6.4 mm at the upper third and 4.8 mm at the middle third of the thigh, while its average transverse diameter is 11.8 mm at the middle third of the thigh. In traumas, US demonstrated compression and displacement of the sciatic nerve in 6 recent hematomas and in 2 hypertrophic ossei calli of the femoral diaphysis. In 2 osteomyelitis cases with a posterior thigh fistula, US showed sciatic nerve involvement by the phlogistic process. Moreover, US allowed an old thick thrombosis of a satellite vein of the sciatic nerve to be depicted. In conclusion, the present study has demonstrated that US not only clearly depicts the sciatic nerve but also provides accurate information on its involvement in recent or previous traumas. PMID:8272540

Lazzari, G

1993-11-01

110

The sea anemone Bunodosoma caissarum toxin BcIII modulates the sodium current kinetics of rat dorsal root ganglia neurons and is displaced in a voltage-dependent manner.  

PubMed

Sea anemone toxins bind to site 3 of the sodium channels, which is partially formed by the extracellular linker connecting S3 and S4 segments of domain IV, slowing down the inactivation process. In this work we have characterized the actions of BcIII, a sea anemone polypeptide toxin isolated from Bunodosoma caissarum, on neuronal sodium currents using the patch clamp technique. Neurons of the dorsal root ganglia of Wistar rats (P5-9) in primary culture were used for this study (n=65). The main effects of BcIII were a concentration-dependent increase in the sodium current inactivation time course (IC(50)=2.8 microM) as well as an increase in the current peak amplitude. BcIII did not modify the voltage at which 50% of the channels are activated or inactivated, nor the reversal potential of sodium current. BcIII shows a voltage-dependent action. A progressive acceleration of sodium current fast inactivation with longer conditioning pulses was observed, which was steeper as more depolarizing were the prepulses. The same was observed for other two anemone toxins (CgNa, from Condylactis gigantea and ATX-II, from Anemonia viridis). These results suggest that the binding affinity of sea anemone toxins may be reduced in a voltage-dependent manner, as has been described for alpha-scorpion toxins. PMID:20015459

Salceda, Emilio; López, Omar; Zaharenko, André J; Garateix, Anoland; Soto, Enrique

2010-03-01

111

Directed nerve regeneration enabled by wirelessly powered electrodes printed on a biodegradable polymer.  

PubMed

Wirelessly directed nerve regeneration: inductively powered electrical stimulation circuits on the biodegradable polymer polycaprolactone demonstrate directed regeneration of sensory neurons from a dorsal root ganglion. These circuits, produced using a unique transfer printing process, illustrate progress towards the use of electrical stimulation systems on biodegradable materials to improve peripheral nerve repair functional outcomes. PMID:24376117

Martin, Christopher; Dejardin, Théophile; Hart, Andrew; Riehle, Mathis O; Cumming, David R S

2014-07-01

112

Patient-specific factors in the proximity of the inferior alveolar nerve to the tooth apex  

PubMed Central

Objectives: To evaluate whether age and gender differences are predictive factors for inferior alveolar nerve position with respect to mandibular first molar roots. Study Design: Cone-beam computed tomography scans [0.2-mm3 voxel size; n = 200 (100 males, 100 females)] of patients aged 15–65 years showing mandibular first and second molars were included in this study. Patients with pathoses that might affect inferior alveolar nerve position, including second molar and/or first premolar extraction, were excluded. Fourteen measurements (mm) were taken from the inferior alveolar nerve to the mesial and distal root apices. Subjects were grouped by age and gender. Data were analysed using two-way analyses of variance with post hoc Bonferroni corrections. Results: The distance from the inferior alveolar nerve to the root apices was smaller in females than males, regardless of age (p < 0.01). Distal roots were closer to the nerve than mesial roots in both genders (p < 0.05). Total buccolingual mandibular length (at 3-mm apical level) was shorter in females than males (p < 0.01) but mean buccolingual mandibular width at the level of the inferior alveolar canal did not differ. Nerve–root apex distances were significantly shorter in males and females aged 16–25 and 56–65 years than in other age groups (p < 0.01). Conclusions: The distance between inferior alveolar nerve and mandibular first molar roots depends upon the age and gender: it is shorter in females than in males and in subjects aged 16–25 years and >55 years than in other age groups. Key words:Age, cone-beam computed tomography, inferior alveolar nerve, root apex, gender. PMID:22926478

Adigüzel, Özkan; Kaya, Sadullah; Akku?, Zeki

2012-01-01

113

[Nerve sheath tumours].  

PubMed

Peripheral nerve sheath tumors are common neoplasms in daily practice. Diagnosis and classification of most conventional peripheral nerve sheath tumors are relatively straightforward for the experienced observer; but on occasion, they are diagnostically challenging (especially with locally aggressive and malignant tumors). This article aims to provide an update of the data (clinical, histological, immunohistochemistry and genomic) of benign, intermediate and malignant peripheral nerve sheath tumors, thanks to the latest WHO "Classification of Tumors of Soft Tissue and Bone", published in 2013, which includes a new chapter on "Nerve Sheath Tumors". Advances in molecular biology have provided new insights into the nature of the various peripheral nerve sheath tumors, and have begun to suggest novel targeted therapeutic approaches. PMID:25541115

Le Guellec, Sophie

2015-01-01

114

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, Marshall G. (Woodside, CA)

1985-01-01

115

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, M.G.

1984-04-20

116

Optical displacement sensor  

DOEpatents

An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

Carr, Dustin W. (Albuquerque, NM)

2008-04-08

117

Reflex regulation of airway sympathetic nerves in guinea-pigs  

PubMed Central

Sympathetic nerves innervate the airways of most species but their reflex regulation has been essentially unstudied. Here we demonstrate sympathetic nerve-mediated reflex relaxation of airway smooth muscle measured in situ in the guinea-pig trachea. Retrograde tracing, immunohistochemistry and electrophysiological analysis identified a population of substance P-containing capsaicin-sensitive spinal afferent neurones in the upper thoracic (T1–T4) dorsal root ganglia (DRG) that innervate the airways and lung. After bilateral vagotomy, atropine pretreatment and precontraction of the trachealis with histamine, nebulized capsaicin (10–60 ?m) evoked a 63 ± 7% reversal of the histamine-induced contraction of the trachealis. Either the ?-adrenoceptor antagonist propranolol (2 ?m, administered directly to the trachea) or bilateral sympathetic nerve denervation of the trachea essentially abolished these reflexes (10 ± 9% and 6 ± 4% relaxations, respectively), suggesting that they were mediated primarily, if not exclusively, by sympathetic adrenergic nerve activation. Cutting the upper thoracic dorsal roots carrying the central processes of airway spinal afferents also markedly blocked the relaxations (9 ± 5% relaxation). Comparable inhibitory effects were observed following intravenous pretreatment with neurokinin receptor antagonists (3 ± 7% relaxations). These reflexes were not accompanied by consistent changes in heart rate or blood pressure. By contrast, stimulating the rostral cut ends of the cervical vagus nerves also evoked a sympathetic adrenergic nerve-mediated relaxation that were accompanied by marked alterations in blood pressure. The results indicate that the capsaicin-induced reflex-mediated relaxation of airway smooth muscle following vagotomy is mediated by sequential activation of tachykinin-containing spinal afferent and sympathetic efferent nerves innervating airways. This sympathetic nerve-mediated response may serve to oppose airway contraction induced by parasympathetic nerve activation in the airways. PMID:16581869

Oh, Eun Joo; Mazzone, Stuart B; Canning, Brendan J; Weinreich, Daniel

2006-01-01

118

Spontaneous nerve torsion: unusual cause of radial nerve palsy.  

PubMed

Spontaneous nerve torsion is a rare cause of nerve palsy. We describe a case of nerve torsion affecting the radial nerve in order to inform radiologists of the existence of this condition and subtle features on cross-sectional imaging that can suggest the diagnosis preoperatively. PMID:25244923

Endo, Yoshimi; Miller, Theodore T; Carlson, Erik; Wolfe, Scott W

2015-03-01

119

Advances in nerve repair.  

PubMed

Patients with peripheral nerve injuries face unpredictable and often suboptimal functional outcome, even following standard microsurgical nerve repair. The challenge of improving such outcomes following nerve surgical procedures has interested many research teams, in both clinical and fundamental fields. Some innovative treatments are presently being applied to a widening range of patients, whereas others will require further development before translation to human subjects. This article presents several recent advances in emerging therapies at various stages of clinical application. Nerve transfers have been successfully used in clinical settings, but new indications are being described, enlarging the range of patients who might benefit from them. Brief direct nerve electrical stimulation has been shown to improve nerve regeneration and outcome in animal models and in a small cohort of patients. Further clinical trials are warranted to prove the efficacy of this exciting and easily applicable approach. Animal studies also suggest a tremendous potential for stem and precursor cell therapy. Further studies will lead to a better understanding of their mechanisms of action in nerve repair and potential applications for human patients. PMID:23250767

Khuong, Helene T; Midha, Rajiv

2013-01-01

120

Changes in nerve microcirculation following peripheral nerve compression?  

PubMed Central

Following peripheral nerve compression, peripheral nerve microcirculation plays important roles in regulating the nerve microenvironment and neurotrophic substances, supplying blood and oxygen and maintaining neural conduction and axonal transport. This paper has retrospectively analyzed the articles published in the past 10 years that addressed the relationship between peripheral nerve compression and changes in intraneural microcirculation. In addition, we describe changes in different peripheral nerves, with the aim of providing help for further studies in peripheral nerve microcirculation and understanding its protective mechanism, and exploring new clinical methods for treating peripheral nerve compression from the perspective of neural microcirculation. PMID:25206398

Gao, Yueming; Weng, Changshui; Wang, Xinglin

2013-01-01

121

Anterior interosseous nerve syndrome  

PubMed Central

Objective: We sought to determine lesion sites and spatial lesion patterns in spontaneous anterior interosseous nerve syndrome (AINS) with high-resolution magnetic resonance neurography (MRN). Methods: In 20 patients with AINS and 20 age- and sex-matched controls, MRN of median nerve fascicles was performed at 3T with large longitudinal anatomical coverage (upper arm/elbow/forearm): 135 contiguous axial slices (T2-weighted: echo time/repetition time 52/7,020 ms, time of acquisition: 15 minutes 48 seconds, in-plane resolution: 0.25 × 0.25 mm). Lesion classification was performed by visual inspection and by quantitative analysis of normalized T2 signal after segmentation of median nerve voxels. Results: In all patients and no controls, T2 lesions of individual fascicles were observed within upper arm median nerve trunk and strictly followed a somatotopic/internal topography: affected were those motor fascicles that will form the anterior interosseous nerve further distally while other fascicles were spared. Predominant lesion focus was at a mean distance of 14.6 ± 5.4 cm proximal to the humeroradial joint. Discriminative power of quantitative T2 signal analysis and of qualitative lesion rating was high, with 100% sensitivity and 100% specificity (p < 0.0001). Fascicular T2 lesion patterns were rated as multifocal (n = 17), monofocal (n = 2), or indeterminate (n = 1) by 2 independent observers with strong agreement (kappa = 0.83). Conclusion: It has been difficult to prove the existence of fascicular/partial nerve lesions in spontaneous neuropathies using clinical and electrophysiologic findings. With MRN, fascicular lesions with strict somatotopic organization were observed in upper arm median nerve trunks of patients with AINS. Our data strongly support that AINS in the majority of cases is not a surgically treatable entrapment neuropathy but a multifocal mononeuropathy selectively involving, within the main trunk of the median nerve, the motor fascicles that continue distally to form the anterior interosseous nerve. PMID:24415574

Bäumer, Philipp; Meinck, Hans-Michael; Schiefer, Johannes; Weiler, Markus; Bendszus, Martin; Kele, Henrich

2014-01-01

122

[Transplantation of nerve tissue].  

PubMed

The results of transplantation of various parts of the central and peripheral nervous system are considered. Transplantation of nerve trunks is used clinically, and heterogenous regeneration of the nerves results in reinnervation of tissues and organs. The spinal ganglion transplantation is successfully used in experiments with both embryonic and mature differentiated neurons. Transplantation of different parts of the cortex, some subcortical structures, hyppocampus, hypothalamus, cerebellum and the spinal cord is made using immature neurons. Some attempts have been made to transplant the nerve tissue grown in vitro into a host. PMID:6998434

Chumasov, E I; Chalisova, N I

1980-01-01

123

Suprascapular nerve entrapment.  

PubMed

It is important to be aware of neuropathy involving the suprascapular nerve. While direct trauma to the suprascapular nerve is the usual cause (direct blow to the base of the neck or posterior shoulder, shoulder dislocation or fracture), the problem may result from overuse injuries (such as repetitive tennis serving or spiking of a volley ball), excessive horizontal adduction, weight lifting, backpacking or no apparent reason. These last three years we have operated 8 cases of suprascapular nerve neurolysis at the level of suprascapular incision, and section of the transverse scapular ligament through the back supraspinal approach. PMID:15830964

Corò, L; Azuelos, A; Alexandre, A

2005-01-01

124

Fibrolipomatous hamartoma of median nerve.  

PubMed

Fibrolipomaous hamartoma is a benign neoplasm of nerves, resulting from anomalous growth of fibroadipose tissue of the nerve sheath. The median nerve is the most commonly involved nerve. Magnetic resonance imaging (MRI) features are pathognomonic, showing a coaxial cable-like appearance on axial images and spaghetti-like appearance on coronal images. Preferred management of the lesion is conservative. PMID:17875173

Jain, T P; Srivastava, D N; Mittal, R; Gamanagatti, S

2007-10-01

125

Nerve Growth Factor Decreases in Sympathetic and Sensory Nerves of Rats with Chronic Heart Failure  

PubMed Central

Nerve growth factor (NGF) plays a critical role in the maintenance and survival of both sympathetic and sensory nerves. Also, NGF can regulate receptor expression and neuronal activity in the sympathetic and sensory neurons. Abnormalities in NGF regulation are observed in patients and animals with heart failure (HF). Nevertheless, the effects of chronic HF on the levels of NGF within the sympathetic and sensory nerves are not known. Thus, the ELISA method was used to assess the levels of NGF in the stellate ganglion (SG) and dorsal root ganglion (DRG) neurons of control rats and rats with chronic HF induced by myocardial infarction. Our data show for the first time that the levels of NGF were significantly decreased (P < 0.05) in the SG and DRG neurons 6–20 weeks after ligation of the coronary artery. In addition, a close relation was observed between the NGF levels and the left ventricular function. In conclusion, chronic HF impairs the expression of NGF in the sympathetic and sensory nerves. Given that sensory afferent nerves are engaged in the sympathetic nervous responses to somatic stimulation (i.e. muscle activity during exercise) via a reflex mechanism, our data indicate that NGF is likely responsible for the development of muscle reflex-mediated abnormal sympathetic responsiveness observed in chronic HF. PMID:24913185

Lu, Jian

2014-01-01

126

A novel chondroitin sulfate hydrogel for nerve repair  

NASA Astrophysics Data System (ADS)

Brachial plexus injuries affect numerous patients every year, with very debilitating results. The majority of these cases are very severe, and involve damage to the nerve roots. To date, repair strategies for these injuries address only gross tissue damage, but do not supply cells with adequate regeneration signals. As a result, functional recovery is often severely lacking. Therefore, a chondroitin sulfate hydrogel that delivers neurotrophic signals to damaged neurons is proposed as a scaffold to support nerve root regeneration. Capillary electrophoresis studies revealed that chondroitin sulfate can physically bind with a variety of neurotrophic factors, and cultures of chick dorsal root ganglia demonstrated robust neurite outgrowth in chondroitin sulfate hydrogels. Outgrowth in chondroitin sulfate gels was greater than that observed in control gels of hyaluronic acid. Furthermore, the chondroitin sulfate hydrogel's binding activity with nerve growth factor could be enhanced by incorporation of a synthetic bioactive peptide, as revealed by fluorescence recovery after photobleaching. This enhanced binding was observed only in chondroitin sulfate gels, and not in hyaluronic acid control gels. This enhanced binding activity resulted in enhanced dorsal root ganglion neurite outgrowth in chondroitin sulfate gels. Finally, the growth of regenerating dorsal root ganglia in these gels was imaged using label-free coherent anti-Stokes scattering microscopy. This technique generated detailed, high-quality images of live dorsal root ganglion neurites, which were comparable to fixed, F-actin-stained samples. Taken together, these results demonstrate the viability of this chondroitin sulfate hydrogel to serve as an effective implantable scaffold to aid in nerve root regeneration.

Conovaloff, Aaron William

127

Heavy metal displacement in chelate-irrigated soil during phytoremediation  

Microsoft Academic Search

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates.

M. S Liphadzi; M. B Kirkham

2003-01-01

128

Cervical Radiculopathy (Pinched Nerve)  

MedlinePLUS

... nerve. The medical term for this condition is cervical radiculopathy. Understanding your spine and how it works can help you better understand cervical radiculopathy. Learn more about your spine online at Spine Basics: http://orthoinfo. org/topic. ...

129

Diabetic Nerve Problems  

MedlinePLUS

... at the wrong times. This damage is called diabetic neuropathy. Over half of people with diabetes get ... you change positions quickly Your doctor will diagnose diabetic neuropathy with a physical exam and nerve tests. ...

130

Displacement and Velocity Ratios  

NSDL National Science Digital Library

This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

Bourassa, James; Rosz, John

2011-04-05

131

Modeling root reinforcement using a root-failure Weibull survival function  

NASA Astrophysics Data System (ADS)

Root networks contribute to slope stability through complex interactions with soil that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamics of root turnover, the quantification of root reinforcement on steep slopes is challenging and consequently the calculation of slope stability also. Although considerable progress has been made, some important aspects of root mechanics remain neglected. In this study we address specifically the role of root-strength variability on the mechanical behavior of a root bundle. Many factors contribute to the variability of root mechanical properties even within a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field data sets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the equations of the tensile force, the elasticity of the roots, and the root distribution are the most important steps. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows for the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

Schwarz, M.; Giadrossich, F.; Cohen, D.

2013-11-01

132

Histopathological effects of radiosurgery on a human trigeminal nerve  

PubMed Central

Background: Radiosurgery is a well-established treatment modality for medically refractory trigeminal neuralgia. The exact mechanism of pain relief after radiosurgery is not clearly understood. Histopathology examination of the trigeminal nerve in humans after radiosurgery is rarely performed and has produced controversial results. Case Description: We report on a 45-year-old female who received radiosurgery treatment for trigeminal neuralgia by Cyberknife. A 6-mm portion of the cisternal segment of trigeminal nerve received a dose of 60 Gy. The clinical benefit started 10 days after therapy and continued for 8 months prior to a recurrence of her previous symptoms associated with mild background pain. She underwent microvascular decompression and partial sensory root sectioning. Atrophied trigeminal nerve rootlets were grossly noted intraoperatively under surgical microscope associated with changes in trigeminal nerve color to gray. A biopsy from the inferolateral surface of the nerve proximal to the midcisternal segment showed histological changes in the form of fibrosis and axonal degeneration. Conclusion: This case study supports the evidence of histological damage of the trigeminal nerve fibers after radiosurgery therapy. Whether or not the presence and degree of nerve damage correlate with the degree of clinical benefit and side effects are not revealed by this study and need to be explored in future studies. PMID:24605252

Al-Otaibi, Faisal; Alhindi, Hindi; Alhebshi, Adnan; Albloushi, Monirah; Baeesa, Saleh; Hodaie, Mojgan

2013-01-01

133

Above Water: Buoyancy & Displacement  

NSDL National Science Digital Library

In an investigation called "Shape It!" learners craft tiny boats out of clay, set them afloat on water and then add weight loads to them, in order to explore: how objects stay afloat in water; what the relationship is among surface tension, buoyancy, density and displacement; and how shape, size, and type of material affect an object's ability to remain buoyant. The introductory text discusses how heavy steel ships can float on bodies of water like rivers, bays and oceans.

2013-12-18

134

The Displaced Aggression Questionnaire  

Microsoft Academic Search

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to

Thomas F. Denson; William C. Pedersen; Norman Miller

2006-01-01

135

Deoxyribonucleic Acid synthesis in root cap cells of cultured roots of convolvulus.  

PubMed

Isolated cultured roots of Convolvulus arvensis L. were incubated in 0.2 microcurie per milliliter methyl-(3)H-thymidine for 14 hours, for 64 hours, or for 14 hours followed by transfer to fresh nutrient medium without tritiated thymidine. Autoradiographs of serial, longitudinal sections of roots which were continuously incubated with tritiated thymidine showed that cells of the root cap columella did not undergo DNA synthesis after their formation from the root cap initials. In roots pulse-labeled with tritiated thymidine, the movement of labeled cells through the root cap columella was followed. Labeled cells were displaced at a constant rate of 72 microns per day over a period of 6 to 9 days before they were sloughed off from the root cap. The specialized role of the root cap cells in relation to their distinctive metabolism and longevity is discussed. PMID:16657765

Phillips, H L; Torrey, J G

1971-08-01

136

A displacement-doubling prism  

NASA Astrophysics Data System (ADS)

A novel prism has been devised which can be used in place of the ‘flag' in an optical shadow-sensing type of displacement sensor, for example. In this way, theoretically the displacement sensitivity of the sensor can be doubled. Such a prism has been manufactured, and its displacement-doubling property has been verified.

Lockerbie, Nicholas A.

2014-03-01

137

Repair of sciatic nerve defects using tissue engineered nerves  

PubMed Central

In this study, we constructed tissue-engineered nerves with acellular nerve allografts in Sprague-Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cells of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats. At postoperative 12 weeks, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tissue-engineered nerves was similar to that after autologous nerve grafting, and was higher than that after repair with acellular nerve allografts. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle; regenerated nerve tracts and sprouted branches were connected with motor endplates, as shown by acetylcholinesterase histochemistry combined with silver staining. The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts, and higher than that after repair with acellular nerve allografts. The hind limb motor function at the affected side was significantly improved, indicating that acellular nerve allografts combined with bone marrow mesenchymal stem cell bridging could promote functional recovery of rats with sciatic nerve defects. PMID:25206507

Zhang, Caishun; Lv, Gang

2013-01-01

138

Selective displacement chromatography of proteins.  

PubMed

In contrast to high molecular weight polyelectrolyte displacers, the efficacy of low molecular weight displacers are dependent on both mobile phase salt and displacer concentration. This sensitivity to the operating conditions opens up the possibility of carrying out selective displacement where the product(s) of interest can be selectively displaced while the low affinity impurities can be desorbed in the induced salt gradient ahead of the displacement train, and the high affinity impurities either retained or desorbed in the displacer zone. This type of displacement combines the operational advantages of step gradient and the high resolution inherent in a true displacement process, in a single operation. Theoretical expressions are presented for establishing selective displacement operating conditions (initial salt concentration, displacer concentration) based on the Steric Mass Action parameters of the displacer and the linear Steric Mass Action parameters of the feed proteins. Experimental results are presented to elucidate the concept of selective displacement in both cation and anion exchange systems. A mixture of alpha-lactalbumin and beta-lactoglobulin A and B has been used for anion-exchange systems; a four-protein mixture consisting of ribonuclease B, bovine and horse heart cytochrome c, and lysozyme has been employed in cation exchange systems. This article also demonstrates that on-line monitoring can be readily employed for the selective displacement process, thus facilitating the scale-up and control of the process. This work sets the stage for the development of robust large scale high resolution separations using selective displacement chromatography. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 119-129, 1997. PMID:18636617

Kundu, A; Barnthouse, K A; Cramer, S M

1997-10-20

139

Displacement Data Assimilation  

NASA Astrophysics Data System (ADS)

Geometric corrections are blended with nonlinear/non-Gaussian estimation methods to produced improved data assimilation outcomes on problems where features are critical. Problems of this sort are the estimation of hurricane tracks, tracking jet meandering, front propagation, among many others. The geometric correction is made possible by a data preserving map. It makes corrections on phase, primarily, as well as in the amplitude. The displacement assimilation is embedded in the analysis stage of a nonlinear/non-Gaussian Bayesian data assimilation scheme, such as the path integral method. In addition to showing how the method improves upon the results, as compared to more standard methodologies.

Restrepo, J. M.; Rosenthal, S.; Venkataramani, S.

2013-05-01

140

Fibrolipomatous hamartoma of the inferior calcaneal nerve (Baxter nerve).  

PubMed

Fibrolipomatous hamartoma (FLH) is a rare, benign lesion of the peripheral nerves most frequently involving the median nerve and its digital branches (80 %). Pathognomonic MR features of FLH such as coaxial-cable-like appearance on axial planes and a spaghetti-like appearance on coronal planes have been described by Marom and Helms, obviating the need for diagnostic biopsy. We present a case of fibrolipomatous hamartoma of the inferior calcaneal nerve (Baxter nerve) with associated subcutaneous fat proliferation. PMID:22526881

Zeng, Rong; Frederick-Dyer, Katherine; Ferguson, N Lynn; Lewis, James; Fu, Yitong

2012-09-01

141

Adapting to variable prismatic displacement  

NASA Technical Reports Server (NTRS)

In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

Welch, Robert B.; Cohen, Malcolm M.

1989-01-01

142

Optic nerve hypoplasia in children.  

PubMed Central

Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving. Images PMID:2191713

Zeki, S. M.; Dutton, G. N.

1990-01-01

143

Prolonged nerve blockade delays the onset of neuropathic pain.  

PubMed

Aberrant neuronal activity in injured peripheral nerves is believed to be an important factor in the development of neuropathic pain. Pharmacological blockade of that activity has been shown to mitigate the onset of associated molecular events in the nervous system. However, results in preventing onset of pain behaviors by providing prolonged nerve blockade have been mixed. Furthermore, the experimental techniques used to date to provide that blockade were limited in clinical potential in that they would require surgical implantation. To address these issues, we have used liposomes (SDLs) containing saxitoxin (STX), a site 1 sodium channel blocker, and the glucocorticoid agonist dexamethasone to provide nerve blocks lasting ~1 wk from a single injection. This formulation is easily injected percutaneously. Animals undergoing spared nerve injury (SNI) developed mechanical allodynia in 1 wk; nerve blockade with a single dose of SDLs (duration of block 6.9 ± 1.2 d) delayed the onset of allodynia by 2 d. Treatment with three sequential SDL injections resulting in a nerve block duration of 18.1 ± 3.4 d delayed the onset of allodynia by 1 mo. This very prolonged blockade decreased activation of astrocytes in the lumbar dorsal horn of the spinal cord due to SNI. Changes in expression of injury-related genes due to SNI in the dorsal root ganglia were not affected by SDLs. These findings suggest that formulations of this kind, which could be easy to apply clinically, can mitigate the development of neuropathic pain. PMID:23045676

Shankarappa, Sahadev A; Tsui, Jonathan H; Kim, Kristine N; Reznor, Gally; Dohlman, Jenny C; Langer, Robert; Kohane, Daniel S

2012-10-23

144

Peroneal nerve entrapment in runners  

Microsoft Academic Search

In a practice involving large groups of athletes, seven runners and one soccer player with peroneal nerve compression neuropathy secondary to exercise have been found. Running incited pain, numbness and tin gling to varying degrees in all patients, and examination after running revealed muscle weakness and a positive percussion test as the nerve winds around the fibular neck. Nerve conduction

Robert E. Leach; Michael B. Purnell; Akiyoshi Saito

1989-01-01

145

Fibrolipoma of the median nerve  

Microsoft Academic Search

Neural fibrolipoma or fibrolipomatous hamartoma is an uncommon benign tumor that usually arises in the median nerve. Fibrofatty tissue proliferates around the nerve and infiltrates the epineurium and perineurium. We report a case of fibrolipomatous hamartoma of the left median nerve in an 18-year-old woman. Our objective was to describe the pathognomonic magnetic resonance imaging features, whose presence obviates the

Kais Nouira; Hend Belhiba; Sofiène Baccar; Anissa Miaaoui; Monia Ben Messaoud; Imène Turki; Ilhem Cheour; Emna Menif

2007-01-01

146

Variable displacement blower  

DOEpatents

A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY); Stotts, Robert E. (Clifton Park, NY); Waring, Douglass R. (Ballston Spa, NY); Folsom, Lawrence R. (Ohain, BE)

1986-01-01

147

Displacement parameter inversion for a novel electromagnetic underground displacement sensor.  

PubMed

Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

2014-01-01

148

The measurement of gas spaces in the roots of aquatic plants — Archimedes revisited  

Microsoft Academic Search

The volume of gas space within the root systems of pot-grown mangrove plants was determined by three methods based on Archimedes' principle: pycnometry, measurement of the upthrust on the root system when immersed in water, and measurement of the volume of water displaced. The results obtained using the upthrust and displacement methods were highly consistent. Although individual estimates obtained by

Mark Curran; Peter James; William G. Allaway

1996-01-01

149

Vagus Nerve Stimulation  

Microsoft Academic Search

Vagus nerve stimulation (VNS) is a safe and reliable treatment adjunct for patients with medically intractable epilepsy. It is both a preventive and an abortive form of therapy, potentially effective against both partial and generalized seizures in adults and children. VNS also has a number of serendipitous effects on mood, memory, and attention and has been approved for the treatment

Arun Paul Amar; Michael L. Levy; Charles Y. Liu; Michael L. J. Apuzzo

2008-01-01

150

Ischemic Nerve Block.  

ERIC Educational Resources Information Center

This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

Williams, Ian D.

151

Segmental thoracic lipomatosis of nerve with nerve territory overgrowth.  

PubMed

Lipomatosis of nerve (LN), or fibrolipomatous hamartoma, is a rare condition of fibrofatty enlargement of the peripheral nerves. It is associated with bony and soft tissue overgrowth in approximately one-third to two-thirds of cases. It most commonly affects the median nerve at the carpal tunnel or digital nerves in the hands and feet. The authors describe a patient with previously diagnosed hemihypertrophy of the trunk who had a history of large thoracic lipomas resected during infancy, a thoracic hump due to adipose proliferation within the thoracic paraspinal musculature, and scoliotic deformity. She had fatty infiltration in the thoracic spinal nerves on MRI, identical to findings pathognomonic of LN at better-known sites. Enlargement of the transverse processes at those levels and thickened ribs were also found. This case appears to be directly analogous to other instances of LN with overgrowth, except that this case involved axial nerves rather than the typical appendicular nerves. PMID:24506247

Mahan, Mark A; Amrami, Kimberly K; Howe, B Matthew; Spinner, Robert J

2014-05-01

152

Strain and stress variations in the human amniotic membrane and fresh corpse autologous sciatic nerve anastomosis in a model of sciatic nerve injury?  

PubMed Central

A 10-mm long sciatic nerve injury model was established in fresh normal Chinese patient cadavers. Amniotic membrane was harvested from healthy maternal placentas and was prepared into multilayered, coiled, tubular specimens. Sciatic nerve injury models were respectively anastomosed using the autologous cadaveric sciatic nerve and human amniotic membrane. Tensile test results showed that maximal loading, maximal displacement, maximal stress, and maximal strain of sciatic nerve injury models anastomosed with human amniotic membrane were greater than those in the autologous nerve anastomosis group. The strain-stress curves of the human amniotic membrane and sciatic nerves indicated exponential change at the first phase, which became elastic deformation curves at the second and third phases, and displayed plastic deformation curves at the fourth phase, at which point the specimens lost their bearing capacity. Experimental findings suggested that human amniotic membranes and autologous sciatic nerves exhibit similar stress-strain curves, good elastic properties, and certain strain and stress capabilities in anastomosis of the injured sciatic nerve.

Peng, Chuangang; Zhang, Qiao; Yang, Qi; Zhu, Qingsan

2012-01-01

153

Sensory nerve conduction of the plantar nerve compared with other nerve conduction tests in rats  

Microsoft Academic Search

ObjectiveIn rats the available techniques for evaluation of sensory nerve conduction are limited. We report a new method of sensory nerve conduction of the plantar nerve using needle electrodes as the recording electrodes behind the medial malleolus and ring electrodes as the stimulating electrodes around the three middle toes.

Katsumi Kurokawa; Diogo F de Almeida; Yun Zhang; Charles D Hébert; John G Page; Karen M Schweikart; Shin J Oh

2004-01-01

154

Histochemical discrimination of fibers in regenerating rat infraorbital nerve  

NASA Technical Reports Server (NTRS)

In rat dorsal root ganglia, histochemical staining of carbonic anhydrase (CA) and cholinesterase (CE) yields a reciprocal pattern of activity: Sensory processes are CA positive and CE negative, whereas motor processes are CA negative and CE positive. In rat infraorbital nerve (a sensory peripheral nerve), we saw extensive CA staining of nearly 100% of the myelinated axons. Although CE reactivity in myelinated axons was extremely rare, we did observe CE staining of unmyelinated autonomic fibers. Four weeks after transection of infraorbital nerves, CA-stained longitudinal sections of the proximal stump demonstrated 3 distinct morphological zones. A fraction of the viable axons retained CA activity to within 2 mm of the distal extent of the stump, and the stain is capable of resolving growth sprouts being regenerated from these fibers. Staining of unmyelinated autonomic fibers in serial sections shows that CE activity was not retained as far distally as is the CA sensory staining.

Wilke, R. A.; Riley, D. A.; Sanger, J. R.

1992-01-01

155

Leptomeningeal metastasis of an intradural malignant peripheral nerve sheath tumor.  

PubMed

Malignant peripheral nerve sheath tumors (MPNST) are defined as any malignant tumor arising from or differentiating towards the peripheral nerve sheath. Intradural MPNST metastases are very rare. We report, to our knowledge, the first case of leptomeningeal metastasis of a MPNST to the spine and intracranial space. A 56-year-old woman with primary intradural MPNST of the S1 nerve root developed leptomeningeal metastases as well as brain metastases 19 months after diagnosis. The patient had a history of non-Hodgkins lymphoma for which she had received irradiation to the spine 15 years prior to this presentation. She had no stigmata of neurofibromatosis type 1. Patients with MPNST may also develop leptomeningeal metastases as demonstrated in this patient with intradural post-radiation MPNST. PMID:23664130

Stark, Andreas M; Mehdorn, H Maximilian

2013-08-01

156

Can amino-functionalized carbon nanotubes carry functional nerve growth factor?  

PubMed Central

Carbon nanotubes can carry protein into cells to induce biological effects. Amino-functionalized carbon nanotubes are soluble and biocompatible, have high reactivity and low toxicity, and can help promote nerve cell growth. In this study, amino-functionalized ethylenediamine-treated multi-walled carbon nanotubes were used to prepare carbon nanotubes-nerve growth factor complexes by non-covalent grafting. The physicochemical properties, cytotoxicity to PC12 and chick embryo dorsal root ganglion, and biological activity of the carbon nanotubes-nerve growth factor complexes were investigated. The results showed that amino functionalization improved carbon nanotubes-nerve growth factor complex dispersibility, reduced their toxicity to PC12 cells, and promoted PC12 cell differentiation and chick embryo dorsal root ganglion. PMID:25206814

Chen, Wen; Xiong, Qing; Ren, Quanxia; Guo, Yake; Li, Gao

2014-01-01

157

Bidirectional inhibitory interactions between the embryonic chicken metanephros and lumbosacral nerves in vitro.  

PubMed

During chicken embryonic development the metanephros forms from the uretic duct at embryonic day (E) 7. As the metanephric tissue develops between E7 and E10, it comes into close apposition with lumbosacral nerves. Coculturing of metanephric and nerve explants demonstrated that the Schwann cells of the sciatic nerve inhibit the migration of metanephric cells in a contact-dependent manner. Conversely, metanephric cells inhibit dorsal root ganglion axon extension in a contact-dependent manner. However, metanephric cells are not inhibited by contact with growth cones or axons. Dorsal root ganglion growth cones become sensitive to the inhibitory signals on the surfaces of metanephric cells around E8, a time when the metanephros is expanding into the territory occupied by nerves in vivo. These observations demonstrate inhibitory bidirectional tissue-tissue interactions in vitro and provide a novel model system for the study of contact-based guidance of both neuronal and non-neuronal cell migration. PMID:15305299

Silver, Lee; Qiang, Liang; Loudon, Robert; Gallo, Gianluca

2004-09-01

158

Root gravitropism  

NASA Technical Reports Server (NTRS)

When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

Masson, P. H.

1995-01-01

159

TPCP: Armillaria Root Rot ARMILLARIA ROOT ROT  

E-print Network

TPCP: Armillaria Root Rot ARMILLARIA ROOT ROT INTRODUCTION A sometimes devastating root rot fungus. Armillaria root rot usually becomes apparent when indigenous forests are cleared for afforestation large indigenous trees In forestry situations, Armillaria root rot has been recorded on both pines

160

Regenerative rotary displacer Stirling engine  

Microsoft Academic Search

A few rotary displacer Stirling engines whose displacers have one gas pocket space at one side, and rotate in a main enclosed cylinder, which is heated from one side and cooled from the opposite side without any regenerator have been tried and studied for a considerable time by the authors. They then tried to improve this engine by equipping them

Naotsugu Isshiki; Luca Raggi; S. Isshiki; K. Hirata; H. Watanabe

1996-01-01

161

Earnings Losses of Displaced Workers  

Microsoft Academic Search

The authors exploit administrative data combining workers' earnings histories with information about their firms to estimate the magnitude and temporal pattern of displaced workers' earnings losses. They find that high-tenure workers separating from distressed firms suffer long-term losses averaging 25 percent per year. In addition, the authors find that displaced workers' losses (1) begin mounting before their separations; (2) depend

Louis S. JACOBSON; ROBERT J. LALONDE; DANIEL G. SULLIVAN

1993-01-01

162

Ultrasound of Peripheral Nerves  

PubMed Central

Over the last decade, neuromuscular ultrasound has emerged as a useful tool for the diagnosis of peripheral nerve disorders. This article reviews sonographic findings of normal nerves including key quantitative ultrasound measurements that are helpful in the evaluation of focal and possibly generalized peripheral neuropathies. It also discusses several recent papers outlining the evidence base for the use of this technology, as well as new findings in compressive, traumatic, and generalized neuropathies. Ultrasound is well suited for use in electrodiagnostic laboratories where physicians, experienced in both the clinical evaluation of patients and the application of hands-on technology, can integrate findings from the patient’s history, physical examination, electrophysiological studies, and imaging for diagnosis and management. PMID:23314937

Suk, Jung Im; Walker, Francis O.; Cartwright, Michael S.

2013-01-01

163

Peripheral contributions to the mechanical hyperalgesia following a lumbar 5 spinal nerve lesion in rats  

Microsoft Academic Search

Using lumbar 5 (L5) dorsal root rhizotomy-bearing rats, we examined the extent to which L5 spinal nerve lesion (SNL)-induced mechanical hyperalgesia was governed by two peripheral components, that is Wallerian degeneration (WD) and peripherally-propagating injury discharge (PID). The contribution of WD to SNL-induced hyperalgesia was studied by excluding PID with lidocaine treatment that blocked nerve conduction temporarily, but completely at

J. H. Jang; B. H. Lee; T. S. Nam; J. W. Kim; D. W. Kim; J. W. Leem

2010-01-01

164

Peripheral nerve sheath tumor in a subadult golden eagle (Aquila chrysaetos).  

PubMed

A 5-year-old, female golden eagle (Aquila chrysaetos) was admitted with tetraplegia that progressed to a nonambulatory, spastic tetraparesis after a few days of treatment. Clinical and radiologic examinations, including radiography, computed tomography scan, and myelography, were indicative of neoplasia involving a spinal nerve root. Postmortem magnetic resonance imaging and necropsy findings confirmed the diagnosis of a peripheral nerve sheath neoplasia, not, to our knowledge, previously reported in a raptor. PMID:24881155

Wernick, Morena Bernadette; Dennler, Matthias; Beckmann, Kathrin; Schybli, Martina; Albini, Sarah; Hoop, Richard K; Steffen, Frank; Kircher, Patrick; Hatt, Jean-Michel

2014-03-01

165

Nerve allografts and conduits in peripheral nerve repair.  

PubMed

Since the last update on nerve conduits and allograft in 2000, investigations have established the efficacy of these alternatives to autograft in the repair of small sensory neural gaps. However, limited insights into the biology of the regenerating nerve continue to preclude intelligent conduit design. Ongoing discoveries in neuroscience and biomaterial engineering hold promise for the eventual development of allograft and conduits with potential of surpassing nerve autografts in clinical efficacy. In this review, we summarize the history, recent advances, and emerging developments in nerve conduits and allograft. PMID:23895714

Lin, Michael Y; Manzano, Givenchy; Gupta, Ranjan

2013-08-01

166

An analytical fiber bundle model for pullout mechanics of root bundles  

NASA Astrophysics Data System (ADS)

Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, ?, that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If ? < 1, small roots break first; if ? > 1, large roots break first. When ? = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of ? is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without changing the distribution's shape increases both the maximum force and corresponding displacement. Estimates of the maximum pullout forces for bundles of 100 roots with identical diameter distribution for different species range from less than 1 kN for barley (Hordeum vulgare) to almost 16 kN for pistachio (Pistacia lentiscus). The model explains why a commonly used assumption that all roots break simultaneously overpredicts the maximum pullout force by a factor of about 1.6-2. This ratio may exceed 3 for diameter distributions that have a large number of small roots like the exponential distribution.

Cohen, D.; Schwarz, M.; Or, D.

2011-09-01

167

Oxaliplatin induces hypomyelination and reduced neuregulin 1 expression in the rat sciatic nerve.  

PubMed

Oxaliplatin causes severe peripheral neuropathy. In this study, we examined hypomyelination in the peripheral nerve in oxaliplatin-induced neuropathy rat model. Gene expression of neuregulin 1 (NRG1), a myelination regulatory factor, is reduced in the dorsal root ganglion (DRG) in DNA microarray analysis. Oxaliplatin increased the g-ratio and reduced levels of myelin protein zero in sciatic nerve, suggesting the hypomyelination. Moreover, oxaliplatin reduced NRG1 mRNA levels in the DRG and decreased levels of cleaved NRG1 type III protein in the sciatic nerve. Our results indicate that oxaliplatin induces hypomyelination and reduced NRG1 expression. PMID:24530887

Tsutsumi, Kuniaki; Yamashita, Yuji; Ushio, Soichiro; Kawashiri, Takehiro; Kaname, Takanori; Fujita, Shunsuke; Oishi, Ryozo; Egashira, Nobuaki

2014-03-01

168

Biosynthesis and transport of gangliosides in peripheral nerve  

SciTech Connect

Radiolabelled glucosamine was injected into L-7 dorsal root ganglion (DRG) of rabbits. At several different times after injection DRG, lumbosacral trunks (LST) and sciatic nerves (SN) were removed and gangliosides extracted. Two and 3 weeks after injection the amounts of radioactivity in the ganglioside fractions of LST and SN were significantly higher than at days 1 and 2. The TCA soluble radioactivity decreased dramatically over the same time period. Colchicine prevented the appearance of radiolabelled lipid in LST and SN. From these experiments the authors conclude that some ganglioside is synthesized in the neuronal cell bodies of DRG and transported in the axons of the sciatic nerve. In another experiment the sciatic nerve was transected and ends separated to prevent regeneration. There was no difference in the amount of radiolabelled ganglioside that was isolated from DRG or LST of transected nerves compared with control nerves. The behavior of several potential acid soluble contaminants was studied in several steps used to isolate gangliosides. Of those studied only CMP-NeuAc could cause significant contamination of the final ganglioside preparation.

Yates, A.J.; Tipnis, U.R.; Hofteig, J.H.; Warner, J.K.

1984-01-01

169

Neurotrophin releasing single and multiple lumen nerve conduits  

PubMed Central

Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and processed by gas foaming. The porosity and mechanical properties of the constructs were regulated by the ratio of porogen to polymer microsphere. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing the protein with microspheres or encapsulating the protein within microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by method of incorporation and polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by its ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). In vivo results indicate that conduits retain their original architecture, and allow for cellular infiltration into the channels. Polymer conduits with controllable lumen diameters and protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth. PMID:15911044

Yang, Yang; De Laporte, Laura; Rives, Christopher B.; Jang, Jae-Hyung; Lin, Wei-Chun; Shull, Kenneth R.; Shea, Lonnie D.

2008-01-01

170

Robotic excision of a pre-coccygeal nerve root tumor  

PubMed Central

Pre-coccygeal ganglioneuroma is a rare clinical entity that presents incidentally or with non-specific symptoms. We present a case of a 25 year old housewife who was incidentally diagnosed with pre-coccygeal ganglioneuroma while getting investigated for primary infertility. The patient had no specific complaints except for irregular menstruation which had started 8 months back. Magnetic resonance imaging (MRI) was suggestive of a presacral and pre-coccygeal lesion. Resection of the tumor was done through the anterior approach using the da Vinci Si robotic system. Two robotic arms and one assistant port were used to completely excise the tumor. Robotic excision of such a tumor mass located at a relatively inaccessible area allows enhanced precision and 3-dimentional (3D) view avoiding damage to important surrounding structures. PMID:25598609

Palep, Jaydeep H.; Mistry, Sheetal; Kumar, Abhaya; Munshi, Mihir; Puranik, Meenakshi; Pednekar, Abhinav

2015-01-01

171

Lumbar epidural brucellar abscess causing nerve root compression  

Microsoft Academic Search

Objectives: To evaluate the usefulness of MR sequences for the differential diagnosis of spinal brucellar abscesses which mimic lumbar disc herniation. Methods: We analyzed six patients with brucellar abscesses who had symptoms mimicking lumbar disc herniation. The study group consisted of three women and three men who were 15–67 (mean=37) years old. Patients were imaged in the axial and sagittal

M Ozates; Ü Özkan; Y Bükte; A Ceviz; I Sari; M Simsek

1999-01-01

172

Reduced Renshaw Recurrent Inhibition after Neonatal Sciatic Nerve Crush in Rats  

PubMed Central

Renshaw recurrent inhibition (RI) plays an important gated role in spinal motion circuit. Peripheral nerve injury is a common disease in clinic. Our current research was designed to investigate the change of the recurrent inhibitory function in the spinal cord after the peripheral nerve crush injury in neonatal rat. Sciatic nerve crush was performed on 5-day-old rat puppies and the recurrent inhibition between lateral gastrocnemius-soleus (LG-S) and medial gastrocnemius (MG) motor pools was assessed by conditioning monosynaptic reflexes (MSR) elicited from the sectioned dorsal roots and recorded either from the LG-S and MG nerves by antidromic stimulation of the synergist muscle nerve. Our results demonstrated that the MSR recorded from both LG-S or MG nerves had larger amplitude and longer latency after neonatal sciatic nerve crush. The RI in both LG-S and MG motoneuron pools was significantly reduced to virtual loss (15–20% of the normal RI size) even after a long recovery period upto 30 weeks after nerve crush. Further, the degree of the RI reduction after tibial nerve crush was much less than that after sciatic nerve crush indicatig that the neuron-muscle disconnection time is vital to the recovery of the spinal neuronal circuit function during reinnervation. In addition, sciatic nerve crush injury did not cause any spinal motor neuron loss but severally damaged peripheral muscle structure and function. In conclusion, our results suggest that peripheral nerve injury during neonatal early development period would cause a more sever spinal cord inhibitory circuit damage, particularly to the Renshaw recurrent inhibition pathway, which might be the target of neuroregeneration therapy. PMID:24778886

Shu, Liang; Su, Jingjing; Jing, Lingyan; Huang, Ying; Di, Yu; Peng, Lichao; Liu, Jianren

2014-01-01

173

Fibrolipoma of the median nerve.  

PubMed

Neural fibrolipoma or fibrolipomatous hamartoma is an uncommon benign tumor that usually arises in the median nerve. Fibrofatty tissue proliferates around the nerve and infiltrates the epineurium and perineurium. We report a case of fibrolipomatous hamartoma of the left median nerve in an 18-year-old woman. Our objective was to describe the pathognomonic magnetic resonance imaging features, whose presence obviates the need for a diagnostic biopsy. PMID:17178460

Nouira, Kais; Belhiba, Hend; Baccar, Sofiène; Miaaoui, Anissa; Ben Messaoud, Monia; Turki, Imène; Cheour, Ilhem; Menif, Emna

2007-01-01

174

Literature Review of Displacement Ventilation  

E-print Network

Performance Evaluation and Design Guidelines for Displacement Ventilation” by Chen and Clicksman (2003), were used to begin the literature search. Their references include papers, articles, and web sites presenting major contributions to the understanding...

Cho, S.; Im, P.; Haberl, J. S.

175

In vivo nerve-macrophage interactions following peripheral nerve injury  

PubMed Central

In vertebrates, the peripheral nervous system has retained its regenerative capacity, enabling severed axons to reconnect with their original synaptic targets. While it is well documented that a favorable environment is critical for nerve regeneration, the complex cellular interactions between injured nerves with cells in their environment, as well as the functional significance of these interactions, have not been determined in vivo and in real time. Here we provide the first minute-by-minute account of cellular interactions between laser transected motor nerves and macrophages in live intact zebrafish. We show that macrophages arrive at the lesion site long before axon fragmentation, much earlier than previously thought. Moreover, we find that axon fragmentation triggers macrophage invasion into the nerve to engulf axonal debris, and that delaying nerve fragmentation in a Wlds model does not alter macrophage recruitment but induces a previously unknown ‘nerve scanning’ behavior, suggesting that macrophage recruitment and subsequent nerve invasion are controlled by separate mechanisms. Finally, we demonstrate that macrophage recruitment, thought to be dependent on Schwann cell derived signals, occurs independently of Schwann cells. Thus, live cell imaging defines novel cellular and functional interactions between injured nerves and immune cells. PMID:22423110

Rosenberg, Allison; Wolman, Marc A.; Franzini-Armstrong, Clara; Granato, Michael

2012-01-01

176

Peripheral nerve repair with nerve growth factor and fibrin matrix  

Microsoft Academic Search

A fibrin sealant matrix (FS) with or without a nerve growth factor (NGF) has been used to improve the recovery of severed peripheral nerves, and these have been compared with the results of using only the standard epineural suture (SUT). Regeneration in the early phase (up to 6 days) was measured by the pinch test. The functional recovery process (up

L. Zeng; A. Worseg; H. Redl; G. Schlag

1994-01-01

177

Nerve-pulse interactions  

SciTech Connect

Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

Scott, A.C.

1982-01-01

178

Managing Chemotherapy Side Effects: Nerve Changes  

MedlinePLUS

... institutes of health Managing Chemotherapy Side Effects Nerve Changes “My fingers and toes felt numb and tingly. ... getting cuts, I always wore shoes.” About nerve changes Some chemotherapy can cause nerve problems. You may ...

179

Effects of nerve growth factor on nerve regeneration after corneal nerve damage  

PubMed Central

The study aims to determine the relation between the effects of mouse nerve growth factor (mNGF) and nerve regeneration after corneal surgery nerve damage. Mechanical nerve injury animal model was established by LASIK (the excimer laser keratomileusis) surgery in 12 Belgian rabbits. mNGF and the balanced salt solution (BBS) were alternatively administered in the left and right eye two times every day for 8 weeks. The morphous and growth of the sub-basal nerve plexus and superficial stroma were observed by in vivo confocal microscopy at the end of weeks 1, 2, 4 and 8 after the surgery. The animal model is successfully established. The morphology and density of corneal nerve have been observed and demonstrated by confocal microscopy. A systematic administration of mNGF can significantly promote the nerve regeneration at the end of weeks 1, 2, 4 and 8, which comparing to the administration of balanced salt solution (P < 0.05). mNGF has effect on sub-basal nerve plexus and superficial stroma after corneal nerve damage which is caused by LASIK. The experimental results suggested that the mNGF may solve the problem of dry eye after LASIK. PMID:25550989

Ma, Ke; Yan, Naihong; Huang, Yongzhi; Cao, Guiqun; Deng, Jie; Deng, Yingping

2014-01-01

180

A novel linear displacement sensor  

NASA Astrophysics Data System (ADS)

With development of time grating technology in the past 10 years, the theory of using time to measure spatial displacement has been completed greatly. In the study of time grating, one novel linear displacement sensor is proposed based on the measurement principles of time grating. The measurement principles of linear displacement are similar to that of angular displacement. Both of them need one endless coordinate with uniform velocity. The theory of linear AC motor is used, and the three-phase winding with equal division space of 120° and three-phase exciting signal with uniform time are utilized to generate the endless moving coordinate with uniform velocity. The magnetic traveling wave arises from the left endpoint and disappears in the right endpoint, and it travels pole pitch distance of W during the periodic time of T with the uniform velocity. When magnetic traveling wave passes by the static probe and the moving probe, the electric signals will be induced on the winding, respectively. Therefore, the linear displacement can be achieved by comparing the phase between the two output induced signals from he static probe and the moving probe. Furthermore, in order to improve the machining technique, four kinds of winding framework are designed to employ. The experimental results show that advantages and disadvantages both exist in the design methods and the precision of experiment results reaches +/-2µm. The next study plan is to choose the most excellent design method through further experiments and improve the precision of displacement sensor greatly.

Yang, Ji-sen; Zhang, Jing; Chen, Xi-hou; Zhang, Tian-heng

2011-12-01

181

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2014 CFR

...Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the...American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines, displacement means...

2014-07-01

182

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2011 CFR

...Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the...American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines, displacement means...

2011-07-01

183

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2010 CFR

...Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the...American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines, displacement means...

2010-07-01

184

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2013 CFR

...Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the...American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines, displacement means...

2013-07-01

185

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2012 CFR

...Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the...American Society for Testing Materials (ASTM) E 29-67. (b) For rotary engines, displacement means...

2012-07-01

186

[A new method of anastomosing severed nerves].  

PubMed

Nerve anastomoses glued with "Fribrinkleber" can be protected from tissue plasminogen-activators both by natural and synthetic inhibitors of fibrinolysis whether administered locally or systemically. The glued nerve-anastomoses do not attain the bond strength of sutured nerves, but show less foreign body reaction. Gluing nerves with Fibrinkleber" combined with inhibition of fibrinolysis would seem to be a good method for reuniting severed nerves. It may be especially useful in nerve transplantation if tension is avoided. PMID:376235

Duspiva, W; Blümel, G; Haas-Denk, S; Wriedt-Lübbe, I

1977-04-01

187

Peripheral nerve lengthening as a regenerative strategy  

PubMed Central

Peripheral nerve injury impairs motor, sensory, and autonomic function, incurring substantial financial costs and diminished quality of life. For large nerve gaps, proximal lesions, or chronic nerve injury, the prognosis for recovery is particularly poor, even with autografts, the current gold standard for treating small to moderate nerve gaps. In vivo elongation of intact proximal stumps towards the injured distal stumps of severed peripheral nerves may offer a promising new strategy to treat nerve injury. This review describes several nerve lengthening strategies, including a novel internal fixator device that enables rapid and distal reconnection of proximal and distal nerve stumps. PMID:25317163

Vaz, Kenneth M.; Brown, Justin M.; Shah, Sameer B.

2014-01-01

188

Restorative effect and mechanism of mecobalamin on sciatic nerve crush injury in mice  

PubMed Central

Mecobalamin, a form of vitamin B12 containing a central metal element (cobalt), is one of the most important mediators of nervous system function. In the clinic, it is often used to accelerate recovery of peripheral nerves, but its molecular mechanism remains unclear. In the present study, we performed sciatic nerve crush injury in mice, followed by daily intraperitoneal administration of mecobalamin (65 ?g/kg or 130 ?g/kg) or saline (negative control). Walking track analysis, histomorphological examination, and quantitative real-time PCR showed that mecobalamin significantly improved functional recovery of the sciatic nerve, thickened the myelin sheath in myelinated nerve fibers, and increased the cross-sectional area of target muscle cells. Furthermore, mecobalamin upregulated mRNA expression of growth associated protein 43 in nerve tissue ipsilateral to the injury, and of neurotrophic factors (nerve growth factor, brain-derived nerve growth factor and ciliary neurotrophic factor) in the L4–6 dorsal root ganglia. Our findings indicate that the molecular mechanism underlying the therapeutic effect of mecobalamin after sciatic nerve injury involves the upregulation of multiple neurotrophic factor genes. PMID:25598780

Gan, Lin; Qian, Minquan; Shi, Keqin; Chen, Gang; Gu, Yanglin; Du, Wei; Zhu, Guoxing

2014-01-01

189

Peripheral nerve conduits: technology update  

PubMed Central

Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS) and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers) and designs (tubular, fibrous, and matrix type) are being presented. PMID:25489251

Arslantunali, D; Dursun, T; Yucel, D; Hasirci, N; Hasirci, V

2014-01-01

190

Morphological pattern of intrinsic nerve plexus distributed on the rabbit heart and interatrial septum.  

PubMed

Although the rabbit is routinely used as the animal model of choice to investigate cardiac electrophysiology, the neuroanatomy of the rabbit heart is not well documented. The aim of this study was to examine the topography of the intrinsic nerve plexus located on the rabbit heart surface and interatrial septum stained histochemically for acetylcholinesterase using pressure-distended whole hearts and whole-mount preparations from 33 Californian rabbits. Mediastinal cardiac nerves entered the venous part of the heart along the root of the right cranial vein (superior caval vein) and at the bifurcation of the pulmonary trunk. The accessing nerves of the venous part of the heart passed into the nerve plexus of heart hilum at the heart base. Nerves approaching the heart extended epicardially and innervated the atria, interatrial septum and ventricles by five nerve subplexuses, i.e. left and middle dorsal, dorsal right atrial, ventral right and left atrial subplexuses. Numerous nerves accessed the arterial part of the arterial part of the heart hilum between the aorta and pulmonary trunk, and distributed onto ventricles by the left and right coronary subplexuses. Clusters of intrinsic cardiac neurons were concentrated at the heart base at the roots of pulmonary veins with some positioned on the infundibulum. The mean number of intrinsic neurons in the rabbit heart is not significantly affected by aging: 2200 ± 262 (range 1517-2788; aged) vs. 2118 ± 108 (range 1513-2822; juvenile). In conclusion, despite anatomic differences in the distribution of intrinsic cardiac neurons and the presence of well-developed nerve plexus within the heart hilum, the topography of all seven subplexuses of the intrinsic nerve plexus in rabbit heart corresponds rather well to other mammalian species, including humans. PMID:24527844

Saburkina, Inga; Gukauskiene, Ligita; Rysevaite, Kristina; Brack, Kieran E; Pauza, Audrys G; Pauziene, Neringa; Pauza, Dainius H

2014-05-01

191

Blade Displacement Predictions for the Full-Scale UH-60A Airloads Rotor  

NASA Technical Reports Server (NTRS)

An unsteady Reynolds-Averaged Navier-Stokes solver for unstructured grids is loosely coupled to a rotorcraft comprehensive code and used to simulate two different test conditions from a wind-tunnel test of a full-scale UH-60A rotor. Performance data and sectional airloads from the simulation are compared with corresponding tunnel data to assess the level of fidelity of the aerodynamic aspects of the simulation. The focus then turns to a comparison of the blade displacements, both rigid (blade root) and elastic. Comparisons of computed root motions are made with data from three independent measurement systems. Finally, comparisons are made between computed elastic bending and elastic twist, and the corresponding measurements obtained from a photogrammetry system. Overall the correlation between computed and measured displacements was good, especially for the root pitch and lag motions and the elastic bending deformation. The correlation of root lead-lag motion and elastic twist deformation was less favorable.

Bledron, Robert T.; Lee-Rausch, Elizabeth M.

2014-01-01

192

Displaced rotations of coherent states  

E-print Network

We propose an approach that enables to use it for construction of rotations of coherent states, in particular, it gives a possibility to construct Hadamard gate for the coherent states. Our approach is based on representation of arbitrary one-mode pure state in free-travelling fields, in particular superposition of coherent states (SCSs), in terms of displaced number states with arbitrary amplitude of displacement. Studied optical scheme is based on alternation of photon additions and displacement operators (in general case, photon additions and displacements are required) with seed coherent state to generate both even and odd displaced squeezed SCSs (DSSCSs) regardless of number of used photon additions. It is shown the studied optical scheme is sensitive to seed coherent state provided that other parameters are invariable. Output states approximate with high fidelity either even squeezed SCS or odd SCS shifted relative each other by some value. It enables to construct local rotation operator for coherent states, in particular, Hadamard gate being mainframe element for quantum computation with coherent states. The effects deteriorating quality of output states are considered.

Sergey A. Podoshvedov

2011-08-06

193

Occipital nerve stimulation.  

PubMed

Occipital nerve stimulation (ONS) is a form of neuromodulation therapy aimed at treating intractable headache and craniofacial pain. The therapy utilizes neurostimulating electrodes placed subcutaneously in the occipital region and connected to a permanently implanted programmable pulse generator identical to those used for dorsal column/spinal cord stimulation. The presumed mechanisms of action involve modulation of the trigeminocervical complex, as well as closure of the physiologic pain gate. ONS is a reversible, nondestructive therapy, which can be tailored to a patient's individual needs. Typically, candidates for successful ONS include those patients with migraines, Chiari malformation, or occipital neuralgia. However, recent MRSA infections, unrealistic expectations, and psychiatric comorbidities are generally contraindications. As with any invasive procedure, complications may occur including lead migration, infection, wound erosion, device failure, muscle spasms, and pain. The success of this therapy is dependent on careful patient selection, a preimplantation trial, meticulous implantation technique, programming strategies, and complication avoidance. PMID:25411143

Mammis, Antonios; Agarwal, Nitin; Mogilner, Alon Y

2015-01-01

194

Peripheral nerve fibromyxoid sarcoma.  

PubMed

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue neoplasm with metastatic potential and needs to be recognized as such, because it can be mistaken for other types of sarcoma due to its unremarkable appearance. This 49-year-old man presented with an approximately 5-cm mass on the anteromedial aspect of his left thigh that slowly increased over 10 years. Clinical symptoms were limited to local discomfort and intermittent distal numbness. Due to the location, imaging findings, and lack of serious symptoms, the initial differential diagnosis favored a schwannoma. An initial biopsy revealed histopathological findings consistent with a perineurioma, although with atypical features. The patient elected to have the mass excised, and the tumor, which arose from a branch of the saphenous nerve, could be separated well from the surrounding soft tissue. Histopathological investigation of the mass displayed characteristic features of a fibromyxoid sarcoma, which was confirmed by subsequent fluorescence in situ hybridization analysis. Due to concerns about infiltration beyond the margins, radical reexcision was advocated and performed, resulting in definite clear surgical margins. At follow-up, the patient had regained full strength with no residual neurological symptoms or any new deficits. He has since been healthy and disease free for a total of 4 years in follow-up. This case documents, to the authors' knowledge, the first observation of an LGFMS associated with a peripheral nerve. It also supports the use of fluorescence in situ hybridization analysis as an essential diagnostic method in establishing the diagnosis of LGFMS. PMID:24766104

Alter, Raanan Y; Wamsley, Christina C; Mullen, John T; Haile, Winta Z; Goldsmith, Jeffrey D; Kasper, Ekkehard M

2014-09-01

195

Peripheral nerve injury of various types, for example complete nerve transection or loose nerve constrictions (Bennett model), results in  

E-print Network

Summary Peripheral nerve injury of various types, for example complete nerve transection or loose-protein-coupled receptors, ion channels, enzymes, and other types of molecules. Peripheral nerve injuries are often transmission. It has been postulated that nerve injury causes sprouting of large-diameter primary afferents

Sandini, Giulio

196

Perceived displacement explains wolfpack effect  

PubMed Central

We investigate the influence of perceived displacement of moving agent-like stimuli on the performance in dynamic interactive tasks. In order to reliably measure perceived displacement we utilize multiple tasks with different task demands. The perceived center of an agent's body is displaced in the direction in which the agent is facing and this perceived displacement is larger than the theoretical position of the center of mass would predict. Furthermore, the displacement in the explicit judgment is dissociated from the displacement obtained by the implicit measures. By manipulating the location of the pivot point, we show that it is not necessary to postulate orientation as an additional cue utilized by perception, as has been suggested by earlier studies. These studies showed that the agent's orientation influences the detection of chasing motion and the detection-related performance in interactive tasks. This influence has been labeled wolfpack effect. In one of the demonstrations of the wolfpack effect participants control a green circle on a display with a computer mouse. It has been shown that participants avoid display areas with agents pointing toward the green circle. Participants do so in favor of areas where the agents point in the direction perpendicular to the circle. We show that this avoidance behavior arises because the agent's pivot point selected by the earlier studies is different from where people locate the center of agent's body. As a consequence, the nominal rotation confounds rotation and translation. We show that the avoidance behavior disappears once the pivot point is set to the center of agent's body. PMID:25566114

Šimkovic, Matúš; Träuble, Birgit

2014-01-01

197

A histochemical determination of the denaturation of the proteins of the nerve cell induced by alcohol  

Microsoft Academic Search

The effect of various concentrations of alcohol on the proteins of the nerve cells of the dorsal root ganglia were studied in cats by a histochemical and photometric method. Denaturation of the proteins was measured in terms of the change in the number of SH-groups, the groups being detected histochemically by means of 5-bromoacetyl-3-nitrobenzoic acid.

V. V. Portugalov; I. B. Krasnov

1964-01-01

198

Regional Aggressive Root Resorption Caused by Neuronal Virus Infection  

PubMed Central

During orthodontic treatment, root resorption can occur unexplainably. No clear distinction has been made between resorption located within specific regions and resorption occurring generally in the dentition. The purpose is to present cases with idiopathic (of unknown origin) root resorption occurring regionally. Two cases of female patients, 26 and 28 years old, referred with aggressive root resorption were investigated clinically and radiographically. Anamnestic information revealed severe virus diseases during childhood, meningitis in one case and whooping cough in the other. One of the patients was treated with dental implants. Virus spreading along nerve paths is a possible explanation for the unexpected resorptions. In both cases, the resorptions began cervically. The extent of the resorption processes in the dentition followed the virus infected nerve paths and the resorption process stopped when reaching regions that were innervated differently and not infected by virus. In one case, histological examination revealed multinuclear dentinoclasts. The pattern of resorption in the two cases indicates that innervation is a factor, which under normal conditions may protect the root surface against resorption. Therefore, the normal nerve pattern is important for diagnostics and for predicting the course of severe unexpected root resorption. PMID:23097724

Kjær, Inger; Strøm, Carsten; Worsaae, Nils

2012-01-01

199

Silk-tropoelastin protein films for nerve guidance.  

PubMed

Peripheral nerve regeneration may be enhanced through the use of biodegradable thin film biomaterials as highly tuned inner nerve conduit liners. Dorsal root ganglion neuron and Schwann cell responses were studied on protein films comprising silk fibroin blended with recombinant human tropoelastin protein. Tropoelastin significantly improved neurite extension and enhanced Schwann cell process length and cell area, while the silk provided a robust biomaterial template. Silk-tropoelastin blends afforded a 2.4-fold increase in neurite extension, when compared to silk films coated with poly-d-lysine. When patterned by drying on grooved polydimethylsiloxane (3.5?m groove width, 0.5?m groove depth), these protein blends induced both neurite and Schwann cell process alignment. Neurons were functional as assessed using patch-clamping, and displayed action potentials similar to those cultured on poly(lysine)-coated glass. Taken together, silk-tropoelastin films offer useful biomaterial interfacial platforms for nerve cell control, which can be considered for neurite guidance, disease models for neuropathies and surgical peripheral nerve repairs. PMID:25481743

White, James D; Wang, Siran; Weiss, Anthony S; Kaplan, David L

2015-03-01

200

Intraneural ganglion cyst on the external popliteal nerve.  

PubMed

There are many causes for the paralysis of the external sciatic popliteal nerve , such as the intraneural ganglion cyst. In this case, we evaluate a 52-year-old woman with no relevant personal record, who was admitted with paresis of the right foot of 4?months of evolution associated with alterations in the sensitivity that rose up to the posterolateral region of the leg. The diagnosis was based on MR and cyst decompression and disconnection of the articular branch. Given the low incidence of these lesions, their origin is still subject to controversy. The most widely accepted theory is the unifying articular theory described by Spinner in the year 2003. Intraneural ganglion cysts must be included in the differential diagnosis of progressive paralysis of the sciatic nerve, lesions of the nerve root at L5 and nerve sheath tumours that start at the lateral compartment of the knee. The treatment of a fibular intraneural ganglion cyst must be surgical and the operation must be performed as soon as possible. PMID:24891476

Rendon, Diego; Pescador, David; Cano, Carlos; Blanco, Juan

2014-01-01

201

Endometriotic lesions of the lower troncular nerves.  

PubMed

Although exceptional, endometriotic lesions of the troncular nerves of the lower limb may occur and are often diagnosed with delay. We report, hereby, the first case of femoral nerve endometriosis the treatment of which consisted of radical resection with femoral nerve transplant. We completed a review of the literature on sciatic nerve endometriotic lesions and discussed the physiopathology and surgical treatment. PMID:25267476

Niro, J; Fournier, M; Oberlin, C; Le Tohic, A; Panel, P

2014-10-01

202

Regeneration of perivascular adrenergic innervation in rat tibial nerve after nerve crush  

Microsoft Academic Search

Adrenergic innervation of blood vessels in the rat tibial nerve during degeneration and regeneration was studied using the formaldehyde-induced fluorescence method. The left sciatic nerve was crushed with suture threads to produce a 4-mm length of crushed nerve. At 1, 3, 7, 14, 28, 56 and 84 days after nerve crush, degenerative and regenerative changes in the nerve were verified

J. Koistinaho; K. C. Wadhwani; A. Balbo; S. I. Rapoport

1991-01-01

203

Video-Gait Analysis of Functional Recovery of Nerve Repaired with Chitosan Nerve Guides  

E-print Network

Video-Gait Analysis of Functional Recovery of Nerve Repaired with Chitosan Nerve Guides MINAL PATEL assessment of functional sciatic nerve recovery treated with chitosan nerve guides. We used video to functional nerve recovery. The chitosan group showed increased functional improvement compared to the control

VandeVord, Pamela

204

Roots and Shoots  

NSDL National Science Digital Library

In this outdoor activity, learners discover that plants aren't just shoots (stem, branches, leaves, and flowers) growing above ground, but contain plenty of roots growing undergroundâmore than half the mass of a plant can be its roots. Learners dig up "mystery" plants to investigate their root structures, and match them to different types of root systems. Learners also learn about animals found near plant roots and how humans use roots.

Science, Lawrence H.

2008-01-01

205

DISPLACEMENT BASED SEISMIC DESIGN METHODS.  

SciTech Connect

A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

2003-07-15

206

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

207

DISPLACEMENTS OF THE DESIRING MACHINE  

Microsoft Academic Search

The ‘cinematic gaze’ can be conceived today as a kind of metaphorical practice, particularly in relation to viewing Patty Chang's video artwork In Love (2001). Chang's artistic expression theatricalizes familial love and reveals how bodily inscriptions of sexuality and ‘race’ are still predetermined by an affected gaze. The original site of the ‘cinema of displacement’ was in the substitute of

Jane Chin Davidson

2012-01-01

208

Spectrum of optic nerve hypoplasia.  

PubMed Central

Optic nerve hypoplasia is a non-progressive condition characterised by subnormal vision and a subnormal number of optic nerve axons. It may be unilateral or bilateral, isolated or combined with other defects. Analysis of fundus photographs from a series of 7 patients with a stationary abnormality of different degrees showed that the functional defects could be closely correlated with defects in the retinal nerve fibre layer. Our observations show that the condition has a wide range of both functional and anatomical defects and that a subnormal diameter of the optic disc is not a requisite for the diagnosis. Presumably, there is also a wide variety of causes, not only a primary failure of development of retinal ganglion cells. We suggest that optic nerve hypoplasia can be viewed as a non-specific manifestation of damage to the visual system, sustained any time before its full development. Images PMID:629914

Frisén, L.; Holmegaard, L.

1978-01-01

209

Ion Channels in Nerve Membranes  

ERIC Educational Resources Information Center

Discusses research that indicates that nerve membranes, which play a key role in the conduction of impulses, are traversed by protein channels with ion pathways opened and closed by the membrane electric field. (Author/MLH)

Ehrenstein, Gerald

1976-01-01

210

Overview of Optic Nerve Disorders  

MedlinePLUS

... Resources for Help and Information The One-Page Merck Manual of Health Medical Terms Conversion Tables Manuals ... Papilledema Optic Neuritis Ischemic Optic Neuropathy Toxic Amblyopia Merck Manual > Patients & Caregivers > Eye Disorders > Optic Nerve Disorders ...

211

H Wave and Spinal Root Potentials in Neuromonitoring of S1 Root Function during Evacuation of Herniated Disc: Preliminary Results  

PubMed Central

Aim To determine the changes in the tibial H reflex and spinal nerve root potentials (SRPs) of the S1 root during posterior discectomy and the effects of surgical manipulation. Methods Tibial H reflex responses (M and H waves) were intermittently recorded from the soleus muscle by surface electrodes during different stages of surgery in 5 patients with S1 radiculopathy. All patients had Achilles reflex preserved bilateraly and no paresis on manual strength testing preoperatively. SRPs were additionally obtained by direct epidural recordings from the surgically exposed S1 root in 2 of them. Results The variations in the amplitude of H wave were minor and reversible upon the cessation of surgical manipulation of the root, but the H reflex was not lost either temporarily or permanently in any of the patients. Prolongation of H wave latency by up to 18% at the end of surgery in comparison with preoperative value was noticed in 4 patients. However, there was increased degree of desynchronization of the SRP in some phases of the spinal root manipulation, such as root mobilization before the disc incision and retraction during the disc evacuation. H waves and SRPs were continuously present during the surgery. Ankle jerks were preserved postoperatively in all 5 patients. Conclusion Unremarkable variations in H wave latency may be followed by increased SRP desynchronization. Monitoring of the epidurally recorded SRPs seems to be more sensitive to surgical manipulations of the spinal nerve root than the tibial H reflex recordings from the soleus muscle. PMID:16625696

Makovec, Matej; Benedi?i?, Mitja; Bošnjak, Roman

2006-01-01

212

Improved C3-4 transfer for treatment of root avulsion of the brachial plexus upper trunk  

PubMed Central

Experimental rats with root avulsion of the brachial plexus upper trunk were treated with the improved C3-4 transfer for neurotization of C5-6. Results showed that Terzis grooming test scores were significantly increased at 6 months after treatment, the latency of C5-6 motor evoked potential was gradually shortened, and the amplitude was gradually increased. The rate of C3 instead of C5 and the C4 + phrenic nerve instead of C6 myelinated nerve fibers crossing through the anastomotic stoma was approximately 80%. Myelinated nerve fibers were arranged loosely but the thickness of the myelin sheath was similar to that of the healthy side. In clinical applications, 39 patients with root avulsion of the brachial plexus upper trunk were followed for 6 months to 4.5 years after treatment using the improved C3 instead of C5 nerve root transfer and C4 nerve root and phrenic nerve instead of C6 nerve root transfer. Results showed that the strength of the brachial biceps and deltoid muscles recovered to level III–IV, scapular muscle to level III–IV, latissimus dorsi and pectoralis major muscles to above level III, and the brachial triceps muscle to level 0–III. Results showed that the improved C3-4 transfer for root avulsion of the brachial plexus upper trunk in animal models is similar to clinical findings and that C3-4 and the phrenic nerve transfer for neurotization of C5-6 can innervate the avulsed brachial plexus upper trunk and promote the recovery of nerve function in the upper extremity.

Zou, Lin; Cao, Xuecheng; Li, Jing; Liu, Lifeng; Wang, Pingshan; Cai, Jinfang

2012-01-01

213

Platelet-rich plasma gel in combination with Schwann cells for repair of sciatic nerve injury?  

PubMed Central

Bone marrow mesenchymal stem cells were isolated from New Zealand white rabbits, culture-expanded and differentiated into Schwann cell-like cells. Autologous platelet-rich plasma and Schwann cell-like cells were mixed in suspension at a density of 1 × 106 cells/mL, prior to introduction into a poly (lactic-co-glycolic acid) conduit. Fabricated tissue-engineered nerves were implanted into rabbits to bridge 10 mm sciatic nerve defects (platelet-rich plasma group). Controls were established using fibrin as the seeding matrix for Schwann cell-like cells at identical density to construct tissue-engineered nerves (fibrin group). Twelve weeks after implantation, toluidine blue staining and scanning electron microscopy were used to demonstrate an increase in the number of regenerating nerve fibers and thickness of the myelin sheath in the platelet-rich plasma group compared with the fibrin group. Fluoro-gold retrograde labeling revealed that the number of Fluoro-gold-positive neurons in the dorsal root ganglion and the spinal cord anterior horn was greater in the platelet-rich plasma group than in the fibrin group. Electrophysiological examination confirmed that compound muscle action potential and nerve conduction velocity were superior in the platelet-rich plasma group compared with the fibrin group. These results indicate that autologous platelet-rich plasma gel can effectively serve as a seeding matrix for Schwann cell-like cells to construct tissue-engineered nerves to promote peripheral nerve regeneration.

Ye, Fagang; Li, Haiyan; Qiao, Guangxi; Chen, Feng; Tao, Hao; Ji, Aiyu; Hu, Yanling

2012-01-01

214

Nerve reconstruction in lumbosacral plexopathy. Case report and review of the literature.  

PubMed

Neurological injury to the lumbosacral plexus associated with pelvic and sacral fractures has traditionally been treated conservatively, despite significant and often debilitating functional deficits of the lower extremities. The authors report a case of reconstruction of the lumbosacral plexus, including nerve grafting to restore lower-extremity function caused by severe trauma to the pelvis. A 16-year-old boy sustained pelvic and sacral fractures in a motor vehicle accident. After stabilization of his orthopedic injuries, he suffered from paresis of his right gluteal and hamstring muscles and had no motor or sensory function below his knee. Two months later, he underwent reconstruction of his lumbosacral plexus performed using a nerve graft from his L-5 and S-1 nerve roots proximal to the inferior gluteal nerve and distal to a branch to the hamstring muscles. After another 2 months, his recovering saphenous nerve was transferred to the sensory component of the posterior tibial nerve by using cabled sural nerve grafts to restore sensation to the sole of his foot. After 2.5 years, he experienced reinnervation of his gluteal and hamstring muscles and could perceive vibration on the sole of his foot. With the assistance of a foot-drop splint, the patient ambulates well and is able to ski. Operative details and the relevant literature are reviewed. PMID:16206740

Tung, Thomas H; Martin, D Zachary; Novak, Christine B; Lauryssen, Carl; Mackinnon, Susan E

2005-01-01

215

Bilateral peripheral neural activity observed in vivo following unilateral nerve injury  

PubMed Central

Manganese-enhanced magnetic resonance imaging (MRI) is a surrogate method to measure calcium content in nervous system since manganese physiologically follows calcium. Manganese is detectable in MRI and therefore visualizes structures and cell populations that actively regulate calcium. Since calcium is actively recruited for the transmission of action potentials, our purpose is to validate manganese-enhanced MRI for detection of changes in lumbar nerves related to nociception. A neuropathic pain model was created by chronic constrictive injury of the left sciatic nerve of Sprague-Dawley rats. Behavioral measurements, using von Frey’s tests, confirmed the presence of significant allodynia in the left hind limb of animals in the injured group. T1-weighted fast spin echo images were obtained of the lumbar cord and plexus of animals with injured left sciatic nerve and uninjured animals (control) scanned in a 7 Tesla magnet after intraperitoneal manganese chloride administration four weeks after surgery. Lumbar nerve roots and sciatic nerves in the injured group show increased normalized manganese-enhanced MRI signal, representing manganese enhancement, compared to the control group. In conclusion, animals with neuropathic pain in the left hind limb show increased manganese uptake in not only the injured sciatic nerve but also in the contralateral uninjured sciatic nerve on manganese-enhanced MRI in vivo. Although poorly understood, this finding corroborates ex vivo finding of bilateral nociceptive-related molecular changes in the nervous system of unilateral pain models. PMID:23638339

Behera, Deepak; Behera, Subrat; Jacobs, Kathleen E; Biswal, Sandip

2013-01-01

216

Nerve conduction during Wallerian degeneration in the baboon  

Microsoft Academic Search

Conduction in the lateral popliteal nerve of the baboon was studied during the course of Wallerian degeneration. Six nerves were examined. In each case the muscle response to nerve stimulation and the ascending nerve action potential were recorded daily until the nerve became inexcitable. The muscle response to nerve stimulation disappeared after four to five days, but ascending nerve action

R. W. Gilliatt; R. J. Hjorth

1972-01-01

217

Optic Nerve Monitoring  

PubMed Central

Orbital and anterior skull base surgery is generally performed close to the prechiasmatic visual pathway, and clear strategies for detecting and handling visual pathway damage are essential. To overcome the common problem of a missed clinical examination because of an uncooperative or unresponsive patient, flash visual evoked potentials and electroretinograms should be used. These electrophysiologic examination techniques can provide evidence of intact, pathologic, or absent conductivity of the visual pathway when clinical assessment is not feasible. Visual evoked potentials and electroretinograms are thus essential diagnostic procedures not only for primary diagnosis but also for intraoperative evaluation. A decision for or against treatment of a visual pathway injury has to be made as fast as possible due to the enormous importance of the time elapsed with such injuries; this can be achieved additionally using multislice spiral computed tomography. The first-line conservative treatment of choice for such injuries is megadose methylprednisolone therapy. Surgery is used to decompress the orbital compartment by exposure of the intracanalicular part of the optic nerve in the case of optic canal compression. Modern craniomaxillofacial surgery requires detailed consideration of the diagnosis and treatment of traumatic visual pathway damage with the ultimate goal of preserving visual acuity. PMID:24436741

Schumann, Paul; Kokemüller, Horst; Tavassol, Frank; Lindhorst, Daniel; Lemound, Juliana; Essig, Harald; Rücker, Martin; Gellrich, Nils-Claudius

2013-01-01

218

A schwannoma of the S1 dural sleeve was resected while the intact nerve fibers were preserved using a microscope. Report of a case with early MRI findings.  

PubMed

In this report, we describe a small schwannoma of the dural sleeve and mention that it is often difficult to differentiate this tumor from lumbar disc herniation, especially a sequestered hernia, or a discal cyst. Gadolinium-enhanced MR images were a useful preoperative examination modality for differentiating this lesion from other diseases. Microscopically, the intradural tumor was successfully removed. The dura mater of the S1 nerve root was opened microsurgically, allowing the nerve fibers involved in the tumor to be identified. The involved fibers were cut around the tumor, and the lesion was resected while the intact nerve fibers were preserved. Based on histological examination of the resected specimen, the tumor was diagnosed as a schwannoma with multilocular cystic degeneration. Microsurgery allowed the tumor to be removed with minimal impairment from cutting of nerve fibers in the nerve root. PMID:17674301

Kobayashi, S; Uchida, K; Kokubo, Y; Yayama, T; Nakajima, H; Inukai, T; Nomura, E; Baba, H

2007-04-01

219

Crustal Displacements Due to Continental Water Loading  

NASA Technical Reports Server (NTRS)

The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (delta-r(sub M)) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare delta-r(sub M) with observed Global Positioning System (GPS) heights (delta-r(sub O)) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the delta-r(sub O) time series are adjusted by delta-r(sub M), their variances are reduced, on average, by an amount equal to the variance of the delta-r(sub M). Of the delta-r(sub O) time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the delta-r(sub M). The delta-r(sub M) time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

vanDam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallee, D.; Larson, K. M.

2001-01-01

220

Rupture models with dynamically determined breakdown displacement  

USGS Publications Warehouse

The critical breakdown displacement, Dc, in which friction drops to its sliding value, can be made dependent on event size by specifying friction to be a function of variables other than slip. Two such friction laws are examined here. The first is designed to achieve accuracy and smoothness in discrete numerical calculations. Consistent resolution throughout an evolving rupture is achieved by specifying friction as a function of elapsed time after peak stress is reached. Such a time-weakening model produces Dc and fracture energy proportional to the square root of distance rupture has propagated in the case of uniform stress drop. The second friction law is more physically motivated. Energy loss in a damage zone outside the slip zone has the effect of increasing Dc and limiting peak slip velocity (Andrews, 1976). This article demonstrates a converse effect, that artificially limiting slip velocity on a fault in an elastic medium has a toughening effect, increasing fracture energy and Dc proportionally to rupture propagation distance in the case of uniform stress drop. Both the time-weakening and the velocity-toughening models can be used in calculations with heterogeneous stress drop.

Andrews, D.J.

2004-01-01

221

Crustal displacements due to continental water loading  

USGS Publications Warehouse

The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (??rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ??rM with observed Global Positioning System (GPS) heights (??rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ??rO time series are adjusted by ??rM, their variances are reduced, on average, by an amount equal to the variance of the ??rM. Of the ??rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ??rM. The ??rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

Van Dam, T.; Wahr, J.; Milly, P.C.D.; Shmakin, A.B.; Blewitt, G.; Lavallee, D.; Larson, K.M.

2001-01-01

222

Gravitropic curvature of maize roots is not preceded by rootcap asymmetry  

NASA Technical Reports Server (NTRS)

We tested whether the first response to gravistimulation is an asymmetry in the root tip that results from differential growth of the rootcap itself. The displacement of markers on the rootcap surface of maize (Zea mays L. cv. Merit) roots was quantified from videotaped images using customized software. The method was sensitive enough to detect marker displacements down to 15 microns and root curvature as early as 8 min after gravistimulation. No differential growth of the upper and lower sides of the cap occurred before or during root curvature. Fewer than a third of all gravistimulated roots developed an asymmetrical outline of the root tip after curvature had started, and this asymmetry did not occur in the rootcap itself. Our data support the view that the regions of gravitropic sensing and curvature are spatially separate during all phases of gravitropism in maize roots.

Sack, F. D.; Hasenstein, K. H.; Blair, A.

1990-01-01

223

Magnetic-motor-root stimulation: review.  

PubMed

Magnetic stimulation can activate the human central and peripheral nervous systems non-invasively and virtually painlessly. Magnetic stimulation over the spinal enlargements can activate spinal nerves at the neuroforamina (magnetic-neuroforamina stimulation). This stimulation method provides us with information related to the latency of compound-muscle action potential (CMAP), which is usually interpreted as peripheral motor-conduction time (PMCT). However, this stimulation method has faced several problems in clinical applications. One is that supramaximal CMAPs were unobtainable. Another is that magnetic stimulation did not usually activate the spinal nerves in the spinal canal, i.e., the cauda equina, which prevented an evaluation of its conduction. For these reasons, magnetic-neuroforamina stimulation was rarely used to evaluate the conduction of peripheral nerves. It was mainly used to evaluate the conduction of the corticospinal tract using the parameter of central motor-conduction time (CMCT), which was calculated by subtracting PMCT from the latency of motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex. Recently, supramaximal stimulation has been achieved in magnetic-neuroforamina stimulation, and this has contributed to the measurement of both CMAP size and latency. The achievement of supramaximal stimulation is ascribed to the increase in magnetic-stimulator output and a novel coil, the magnetic augmented translumbosacral stimulation (MATS) coil. The most proximal part of the cauda equina can be reliably activated using the MATS coil (magnetic-conus stimulation), thus contributing to the measurement of cauda equina conduction time (CECT) and cortico-conus motor-conduction time (CCCT). These recent developments in magnetic-motor-root stimulation enable us to more precisely evaluate the conduction of the proximal part of peripheral nerves and that of the corticospinal tract for lower-limb muscles. In this review article, we summarise the basic mechanisms, recent topics, clinical applications, comparison to electrical stimulation, pitfalls, safety and additional issues in magnetic-motor-root stimulation. PMID:23485367

Matsumoto, Hideyuki; Hanajima, Ritsuko; Terao, Yasuo; Ugawa, Yoshikazu

2013-06-01

224

THE PRODUCTION OF CARBON DIOXIDE BY NERVE  

PubMed Central

1. A modified Osterhout respiratory apparatus for the detection of CO2 from nerve is described. 2. The lateral-line nerve from the dogfish discharges CO2 at first with a gush for half an hour or so and then steadily at a lower rate for several hours. 3. Simple handling of the nerve does not increase the output of CO2; cutting it revives gush. 4. The CO2 produced by nerve is not escaping simply from a reservoir but is a true nervous metabolite. 5. The rate of discharge of CO2 from a quiescent nerve varied from 0.0071 to 0.0128 mg. per gram of nerve per minute and averaged 0.0095 mg. 6. Stimulated nerve showed an increased rate of CO2 production of 15.8 percent over that of quiescent nerve. 7. The results of these studies indicate that chemical change is a factor in nerve transmission. PMID:19872167

Parker, G. H.

1925-01-01

225

Repeat aortic root replacement  

Microsoft Academic Search

Background. Aortic root replacement in patients who have undergone previous aortic root replacement presents a formidable technical challenge, which may lead to increased surgical mortality.Methods. We reviewed our experience from January 1989 through November 1995. Seven consecutive patients (6 men and 1 woman) underwent eight repeat aortic root replacements. Mean follow-up was 19 months. Previous root replacement had been performed

Chiwon Hahn; Stanley K. C Tam; Gus J Vlahakes; Alan D Hilgenberg; Cary W Akins; Mortimer J Buckley

1998-01-01

226

Knowledge integration and displaced volume  

NSDL National Science Digital Library

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as well as to construct general principles. We distinguished the impact of instruction on students who believed scientific phenomena are governed by principles (cohesive beliefs) versus students who believed that science is a collection of unrelated ldquofactsrdquo (dissociated beliefs). Students typically held multiple models of displacement, using different explanations depending on the form of assessment. For example, we found that 17% of these middle school students made accurate predictions about displacement experiments prior to instruction and 25% could construct an accurate general principle. However, only 12% consistently used the same explanation across assessments. After instruction, students were more accurate and more consistent: over 50% accurately predicted experimental outcomes, 79% gave an accurate general principle, and about 40% gave consistent responses. We found no advantages for enhanced animations over straightforward animated experiments. The reflective integration instruction led to more substantial long-term changes in student understanding than did spontaneous integration instruction. Furthermore, on a delayed posttest we found that students with cohesive beliefs not only sustained their understanding of displaced volume, but, when exposed to reflective integration instruction, actually continued to construct more predictive views following instruction. In contrast, students with dissociated beliefs made no long-term progress independent of the form of instruction.

Linn, Marcia; Eylon, Bat-Sheva

2006-12-07

227

Retrieving three-dimensional displacement fields of mining areas from a single InSAR pair  

NASA Astrophysics Data System (ADS)

This paper presents a novel method for retrieving three-dimensional (3-D) displacement fields of mining areas from a single interferometric synthetic aperture radar (InSAR) pair. This method fully exploits the mechanism of mining subsidence, specifically the proportional relationship between the horizontal displacement and horizontal gradient of vertical displacements caused by underground mining. This method overcomes the limitations of conventional InSAR techniques that can only measure one-dimensional (1-D) deformation of mining area along the radar line-of-sight direction. The proposed method is first validated with simulated 3-D displacement fields, which are obtained by the FLAC software. The root mean square errors of the 3-D displacements retrieved by the proposed method are 13.7, 27.6 and 3.6 mm for the West-East, North-South, and Up-Down components, respectively. We then apply the proposed method to estimate the 3-D displacements of the Qianyingzi and the Xuzhou coal mines in China, respectively, each along with two Advanced Land Observing Satellite (ALOS) Phased Array Type L-band Synthetic Aperture Radar images. Results show that the estimated 3-D displacement is highly consistent with that of the field surveying. This demonstrates that the proposed method is an effective approach for retrieving 3-D mining displacement fields and will play an important role in mining-related hazard prevention and environment assessment under limited InSAR acquisitions.

Li, Zhi Wei; Yang, Ze Fa; Zhu, Jian Jun; Hu, Jun; Wang, Yun Jia; Li, Pei Xian; Chen, Guo Liang

2015-01-01

228

Pulsed Radiofrequency of Lumbar Dorsal Root Ganglion for Chronic Postamputation Phantom Pain  

PubMed Central

Chronic pain following lower-limb amputation is now a well-known neuropathic, chronic-pain syndrome that usually presents as a combination of phantom and stump pain. Controlling these types of neuropathic pain is always complicated and challenging. If pharmacotherapy does not control the patient’s pain, interventional procedures have to be taken. The aim of this study was to evaluate the efficacy of using pulsed radiofrequency (PRF) on the dorsal root ganglia at the L4 and L5 nerve roots to improve phantom pain. Two patients with phantom pain were selected for the study. After a positive response to segmental nerve blockade at the L4 and L5 nerve roots, PRF was performed on the L4 and L5 dorsal root ganglia. Global clinical improvement was good in one patient, with a 40% decrease in pain on the visual analogue scale (VAS) in 6 months, and moderate in the second patient, with a 30% decrease in pain scores in 4 months. PRF of the dorsal root ganglia at the L4 and L5 nerve roots may be an effective therapeutic option for patients with refractory phantom pain. PMID:24904793

Imani, Farnad; Gharaei, Helen; Rezvani, Mehran

2012-01-01

229

[Paralytic shoulder secondary to post-traumatic peripheral nerve lesions in the adult].  

PubMed

A critical review is presented of the indications for nerve repair or transfer and for palliative operations in the management of paralytic shoulder following traumatic neurological injuries in the adult. Different situations are considered: paralytic shoulder following supraclavicular lesions of the brachial plexus, following retro- and infraclavicular lesions and following lesions to the terminal branches of the plexus (axillary, suprascapular and musculocutaneous nerves) and finally problems related to lesions of the accessory nerve and the long thoracic nerve. I. Supraclavicular lesions of the brachial plexus. In complete (C5 to T1) lesions, the possibilities for nerve repair or transfer are at best limited, and the aim is to restore active flexion of the elbow. Palliative operations may be associated in order to stabilize the shoulder. In case of a complete C5 to T1 root avulsion, amputation at the distal humerus may be considered but is rarely performed combined with shoulder arthrodesis if the trapezius and serratus anterior muscles are functioning. The shoulder may also be stabilized by a ligament plasty using the coracoacromial ligament. In cases where the supraspinatus and long head of the biceps have recovered, but where active external rotation is absent, function may be improved by derotation osteotomy of the humerus. In partial C5,6 or C5,6,7 lesions, the indications for nerve repair and transfer are wider, as well as the indications for muscle transfers. In C5,6 lesions, a neurotization from the accessory nerve to the suprascapular nerve gives 60% satisfactory results; this is also true following treatment of C5,6,7 lesions, whereas restoration of active elbow flexion is obtained in 100% of cases in C5,6 lesions but only in 86% in C5,6,7 lesions. In cases where shoulder function has not been restored, palliative operations may be considered: arthrodesis or, more often, derotation osteotomy of the humerus which can be combined with transfer of the teres major and latissimus dorsi. II. Retro- and infraclavicular lesions of the brachial plexus. Twenty-five percent of the lesions of the brachial plexus occur in the retro- or infraclavicular region and involve the secondary trunks, most commonly the posterior trunk. Nerve repair should be performed early. The shoulder may be affected owing to involvement of the axillary nerve in cases of lesions of the posterior trunk, often associated with a lesion of the suprascapular nerve. Regarding the terminal branches (axillary, suprascapular and musculocutaneous nerves), spontaneous recovery may be expected in a significant proportion of cases but is often delayed (6-9 months), and the problem is to avoid unnecessary operations while not unduly delaying surgical repair in cases where it is indicated. MRI may be useful to delineate those cases where surgery is indicated: repair is usually performed around 6 months following trauma. Isolated lesions of the axillary nerve may be repaired with good results using a nerve graft. The lesion may occur in combination with a lesion of the suprascapular nerve; the latter may be interrupted at several levels. Proximal repair may be performed using a nerve graft; distal lesions are more difficult to repair and may require intramuscular neurotization. Lesions of the musculocutaneous nerve may be repaired with good results using a nerve graft. Lesions of the axillary nerve may be seen associated with lesions of the rotator cuff. The treatment varies according to the age and condition of the patient and according to the condition of the cuff muscles and tendons: in a young patient with avulsion of the tendons from bone, cuff reinsertion is indicated; in an older patient, the cuff must be evaluated by MRI or arthroscan, and repair is indicated unless the cuff tear is not amenable to surgery or there is fatty degeneration of the muscles. Palliative surgery may be indicated in cases seen late or after failed attempts at nerve repair. (ABSTRACT PMID:10216997

Alnot, J Y

1999-03-01

230

Water Mist Suppression in Conjunction with Displacement  

E-print Network

Water Mist Suppression in Conjunction with Displacement Ventilation By Benjamin Piers Hume-2758 #12;#12;Displacement Water Mist System Masters of Fire Engineering Thesis 2003 i A man of genius makes Water Mist System Masters of Fire Engineering Thesis 2003 ii #12;Displacement Water Mist System Masters

Hickman, Mark

231

The case for character displacement in plants  

PubMed Central

The evidence for character displacement as a widespread response to competition is now building. This progress is largely the result of the establishment of rigorous criteria for demonstrating character displacement in the animal literature. There are, however, relatively few well-supported examples of character displacement in plants. This review explores the potential for character displacement in plants by addressing the following questions: (1) Why aren't examples of character displacement in plants more common? (2) What are the requirements for character displacement to occur and how do plant populations meet those requirements? (3) What are the criteria for testing the pattern and process of character displacement and what methods can and have been used to address these criteria in the plant literature? (4) What are some additional approaches for studying character displacement in plants? While more research is needed, the few plant systems in which character displacement hypotheses have been rigorously tested suggest that character displacement may play a role in shaping plant communities. Plants are especially amenable to character displacement studies because of the experimental ease with which they can be used in common gardens, selection analyses, and breeding designs. A deeper investigation of character displacement in plants is critical for a more complete understanding of the ecological and evolutionary processes that permit the coexistence of plant species. PMID:24683467

Beans, Carolyn M

2014-01-01

232

Neuromodulation of the suprascapular nerve.  

PubMed

The shoulder joint is an enarthrodial or ball-and-socket joint. A complex network of anatomic structures endows the human shoulder with tremendous mobility, greater than any other joint in the body. Many pathologies can been found in those patients with chronic shoulder pain. The painful limitation of shoulder motion affects hand and arm motion as well; therefore, it significantly influences work performance and everyday activities as well as the quality of life. Therefore, the treatment of patients with chronic shoulder pain has major social and health economic implications. In this article we present a patient with a complex history of shoulder pathology including 7 surgeries that left the patient with chronic debilitating shoulder pain. She was suffering from chronic pain and limited mobility of the shoulder joint due to adhesive shoulder capsulitis. She was treated with a multimodality approach with the goals of increasing shoulder range of motion and decreasing her pain. This did not provide significant improvement. The suprascapular nerve supplies motor and sensory innervation to the shoulder, and can be easily accessible in the supraspinatus fossa. A suprascapular nerve block dramatically decreased her pain. This clinical observation along with confirmatory nerve block play an important role during the decision-making process for a trial period of electrical neuromodulation. She was followed for 3 months after the permanent implantation of a suprascapular nerve stimulator. Her pain and shoulder range of motion in all planes improved dramatically. Peripheral nerve stimulation (PNS) of the suprascapular nerve, in addition to multimodality pain management, is one approach to the difficult task of treating adhesive capsulitis with accompanying pain and the inability to move the shoulder. We conducted a literature review on PubMed and found no case describing a similar patient to our knowledge. PMID:25415792

Elahi, Foad; Reddy, Chandan G

2014-12-01

233

Nerve lesioning with direct current  

NASA Astrophysics Data System (ADS)

Spastic hypertonus (muscle over-activity due to exaggerated stretch reflexes) often develops in people with stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Lesioning of nerves, e.g. with phenol or botulinum toxin is widely performed to reduce spastic hypertonus. We have explored the use of direct electrical current (DC) to lesion peripheral nerves. In a series of animal experiments, DC reduced muscle force by controlled amounts and the reduction could last several months. We conclude that in some cases controlled DC lesioning may provide an effective alternative to the less controllable molecular treatments available today.

Ravid, E. Natalie; Shi Gan, Liu; Todd, Kathryn; Prochazka, Arthur

2011-02-01

234

Take Charge of Your Diabetes (Nerve Damage)  

MedlinePLUS

... gov . Diabetes Public Health Resource Share Compartir Take Charge of Your Diabetes Some Signs of Diabetic Nerve ... There’s a lot you can do to take charge and prevent nerve damage. A recent study shows ...

235

Solitary sciatic nerve lymphoma as an initial manifestation of diffuse neurolymphomatosis. Case report and review of the literature.  

PubMed

Solitary peripheral nerve lymphomas are exceedingly rare primary manifestations of diffuse peripheral nervous system or central nervous system (CNS) lymphomatosis. A 52-year-old man presented with progressive weakness in gastrocnemius and anterior tibial muscle function, which was associated with radiating pain in the right leg. Magnetic resonance imaging studies revealed a solitary fusiform tumor, extending from the sciatic nerve, at the level of the lesser trochanter of the femur, into the posterior tibial nerve below the popliteal fossa. Intraoperative gross examination found that the tumor diffusely expanded the nerve, but did not extend from or into surrounding muscle or tendons. The final histological diagnosis was a solitary extranodal lymphoma (Burkittlike high-grade B-cell lymphoma). Postoperative staging did not reveal evidence of lymphomatous involvement of other organs, but additional chemo- and radiotherapies were administered. Four months after the surgical biopsy, the patient presented with a right facial nerve palsy. The results of cytological examination of cerebrospinal fluid were positive for the presence of atypical lymphocytes, which was consistent with apparently progressive neurolymphomatosis; however, the results of radiological studies were negative for systemic progression. The patient underwent intrathecal chemotherapy followed by systemic myelosuppressive chemotherapy with bone marrow rescue, but died of respiratory failure while still receiving treatment. Postmortem examination revealed extensive lymphomatosis in the peripheral nerves and spinal nerve roots without evidence of cranial nerve, CNS, or other organ system involvement. The aggressive biological characteristics of these tumors, their management, and pertinent literature are reviewed. PMID:10616097

Quiñones-Hinojosa, A; Friedlander, R M; Boyer, P J; Batchelor, T T; Chiocca, E A

2000-01-01

236

Gravitropic bending of cress roots without contact between amyloplasts and complexes of endoplasmic reticulum  

Microsoft Academic Search

The polar arrangement of cell organelles in Lepidium root statocytes is persistently converted to a physical stratification during lateral centrifugation (the centrifugal force acts perpendicular to the root long axis) or by apically directed centrifugation combined with cytochalasin-treatment. Lateral centrifugation (10 min, 60 min at 10\\\\g or 50\\\\g) causes displacement of amylplasts to the centrifugal anticlinal cell wall and shifting

Marina Wendt; Ling-Long Kuo-Huang; Andreas Sievers

1987-01-01

237

Amyloplast Distribution Directs a Root Gravitropic Reaction  

NASA Astrophysics Data System (ADS)

Immobile higher plants are oriented in the gravitational field due to gravitropim that is a physiological growth reaction and consists of three phases: reception of a gravitational signal by statocytes, its transduction to the elongation zone, and finally the organ bending. As it is known, roots are characterized with positive gravitropism, i. e. they grow in the direction of a gravitational vector, stems - with negative gravitropism, i. e. they grow in the direction opposite to a gravitational vector. According to the Nemec’s and Haberlandt’s starch-statolith hypothesis, amyloplasts in diameter of 1.5 - 3 ? in average, which appear to act as gravity sensors and fulfill a statolythic function in the specialized graviperceptive cells - statocytes, sediment in the direction of a gravitational vector in the distal part of a cell, while a nucleus is in the proximal one. There are reasonable data that confirm the amyloplasts-statoliths participation in gravity perception: 1) correlation between the statoliths localization and the site of gravity sensing, 2) significant redistribution (sedimentation) of amyloplasts in statocytes under gravistimulation in comparison with other cell organelles, 3) root decreased ability to react on gravity under starch removal from amyloplasts, 4) starchless Arabidopsis thaliana mutants are agravitropic, 5) amyloplasts-statoliths do not sediment in the absence of the gravitational vector and are in different parts or more concentrated in the center of statocytes. Plant tropisms have been intensively studied for many decades and continue to be investigated. Nevertheless, the mechanisms by which plants do so is still not clearly explained and many questions on gravisensing and graviresponse remain unanswered. Even accepted hypotheses are now being questioned and recent data are critically evaluated. Although the available data show the Ca2+ and cytoskeleton participation in graviperception and signal transduction, the clear evidence with regard to the participation of calcium ions and cytoskeletal elements in these processes is therefore substantial but still circumstantial and requires new experimental data. Using a new model - weak combined magnetic fields (CMFs), which elicit a variety of responses in plants, growth rate and fresh weight, seed germination, Ca2+ concentration, membrane permeability, with a frequency resonance to cyclotron frequency of calcium ions, we firstly showed that a root positive gravitropic reaction changes on a negative one. In this case, the paradoxical displacement of amylopasts-statoliths to the upper longitudinal cell wall of statocytes occurred in the direction opposite to a gravitational vector. Displacement of amyloplasts, which contain the abundance of free Ca2+ in the stroma, was accompanied with Ca2+ redistribution in the same direction in the cytosol and increasing around amyloplasts in comparison with the state magnetic field. In the elongation zone, calcium ions accumulated in the upper site of a gravistimulated root unlike a positive gravitropic reaction, and a root is bending in the same direction in which amyloplasts are displacing. It seems that a root gravitropic reaction, if it began, occurs by an usual physiological way resulting in root bending with an opposite sign. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. Peculiarities of calcium ion redistribution in statocytes under gravistimulation in such combined magnetic field are a new additional evidence of a Ca2+ ion significant role in gravitropism. Thus, our data support the starch-statolith hypothesis but also pose the question as to which forces displace amyloplasts against the gravity vector? We hope that these data will stimulate new research to better understand the mechanisms of plant graviperception and graviresponse. Gravistimulation of a root in the CMF with the frequency resonance to the cyclotron frequency of Ca2+ ions is an effective model for future

Kordyum, Elizabeth

238

Microsurgical anatomy of lumbosacral nerve rootlets for highly selective rhizotomy in chronic spinal cord injury.  

PubMed

It is known that selective sacral roots rhizotomy is effective for relieving the neurogenic bladder associated with spinal cord injury. The goal of this study is to review the surgical anatomy of the lumbosacral nerve rootlets and to provide some morphological bases for highly selective sacral roots rhizotomy. Spinal cord dissections were performed on five cadavers under surgical microscope. At each spinal cord segment, we recorded the number, diameter and length of the rootlets, subbundles and bundles from the L1 to S2 spinal segments, and the length of the dorsal/ventral root entry zone. Peripheral nervous system myelin was examined by immunohistochemistry. We found: (1) the ventral or the dorsal root of the lumbosacral segment of the spinal cord was divided into one to three nerve bundles and each bundle was subdivided into one to three subbundles. Each subbundle further gave out two to three rootlets connected with the spinal cord; (2) there were no significant differences in the number of rootlets within the L1 to S2 segments, but the size of rootlets and the length of nerve roots varied (P < 0.05); and (3) the more myelinated fibers a rootlet contained, the larger transection area it had. The area of peripheral nervous system myelin positive cells and the total area of rootlets were correlated (P < 0.001). Thus, during highly selective sacral roots rhizotomy, the ventral and dorsal roots can be divided into several bundles of rootlets, and we could initially distinct the rootlets by their diameters. PMID:21089050

Zhou, Mou-Wang; Wang, Wen-Ting; Huang, Hong-Shi; Zhu, Gen-Ying; Chen, Ya-Ping; Zhou, Chang-Man

2010-12-01

239

Proximal Sciatic Nerve Intraneural Ganglion Cyst  

PubMed Central

Intraneural ganglion cysts are nonneoplastic, mucinous cysts within the epineurium of peripheral nerves which usually involve the peroneal nerve at the knee. A 37-year-old female presented with progressive left buttock and posterior thigh pain. Magnetic resonance imaging revealed a sciatic nerve mass at the sacral notch which was subsequently revealed to be an intraneural ganglion cyst. An intraneural ganglion cyst confined to the proximal sciatic nerve has only been reported once prior to 2009. PMID:20069041

Swartz, Karin R.; Wilson, Dianne; Boland, Michael; Fee, Dominic B.

2009-01-01

240

Root Development and Nutrient Uptake  

Microsoft Academic Search

Root system formation proceeds in close coordination with shoot growth. Accordingly, root growth and its functions are regulated tightly by the shoot through materials cycling between roots and shoots. A plant root system consists of different kinds of roots that differ in morphology and functions. The spatial configuration and distribution of these roots determine root system architecture in the soil,

H. Wang; Y. Inukai; A. Yamauchi

2006-01-01

241

A cadaver study to determine the minimum volume of methylene blue or black naphthol required to completely color the nerves relevant for anesthesia during breast surgery.  

PubMed

Regional anesthesia for breast surgery may require a large amount of local anesthetic solution to provide an adequate blockade of all relevant structures. The purpose of this study was to determine the minimal volume of fluid required to anesthetize all nerves to adequately provide anesthesia for breast surgery. This is an open randomized study. Cadavers were embalmed using Thiel's technique and were injected with different volumes of 0.2% methylene blue or 0.2% black naphthol for a superficial cervical plexus block (2, 5, 10, or 15 mL), an interscalene block (5, 10, 15, or 20 mL), paravertebral blocks from C(8) to T(6), and intercostal nerve blocks at 8 cm from the midline (2 or 3 mL) under ultrasound-guided or assisted techniques. The following minimal volumes of fluid were required for complete coloration of the nerves: 2 mL for the supraclavicular nerves; 20 mL for the nerve roots from C(5) to C(7), inclusive, if intraneural injection was avoided; 3 mL per root for the nerve roots from C(8) to T(6), inclusive, for a paravertebral block; and 2 mL per nerve for intercostal nerve blocks at T(4) and lower. With 20 mL of solution at the interscalene level, the roots of C(3) and C(4) were also colored; therefore, a separate injection for the supraclavicular nerves was unnecessary. We conclude that regional anesthesia for complex breast surgery can be achieved with a volume of local anesthetic as low as 41 mL. PMID:21322042

Guay, Joanne; Grabs, Detlev

2011-03-01

242

Carbon-nanotube-interfaced glass fiber scaffold for regeneration of transected sciatic nerve.  

PubMed

Carbon nanotubes (CNTs), with their unique and unprecedented properties, have become very popular for the repair of tissues, particularly for those requiring electrical stimuli. Whilst most reports have demonstrated in vitro neural cell responses of the CNTs, few studies have been performed on the in vivo efficacy of CNT-interfaced biomaterials in the repair and regeneration of neural tissues. Thus, we report here for the first time the in vivo functions of CNT-interfaced nerve conduits in the regeneration of transected rat sciatic nerve. Aminated CNTs were chemically tethered onto the surface of aligned phosphate glass microfibers (PGFs) and CNT-interfaced PGFs (CNT-PGFs) were successfully placed into three-dimensional poly(l/d-lactic acid) (PLDLA) tubes. An in vitro study confirmed that neurites of dorsal root ganglion outgrew actively along the aligned CNT-PGFs and that the CNT interfacing significantly increased the maximal neurite length. Sixteen weeks after implantation of a CNT-PGF nerve conduit into the 10mm gap of a transected rat sciatic nerve, the number of regenerating axons crossing the scaffold, the cross-sectional area of the re-innervated muscles and the electrophysiological findings were all significantly improved by the interfacing with CNTs. This first in vivo effect of using a CNT-interfaced scaffold in the regeneration process of a transected rat sciatic nerve strongly supports the potential use of CNT-interfaced PGFs at the interface between the nerve conduit and peripheral neural tissues. PMID:25463487

Ahn, Hong-Sun; Hwang, Ji-Young; Kim, Min Soo; Lee, Ja-Yeon; Kim, Jong-Wan; Kim, Hyun-Soo; Shin, Ueon Sang; Knowles, Jonathan C; Kim, Hae-Won; Hyun, Jung Keun

2015-02-01

243

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

Farah, John (M.I.T. P.O. Box 397301, Cambridge, MA 02139)

1999-01-01

244

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

Farah, J.

1999-04-06

245

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

Farah, J.

1995-05-30

246

Electrical Conduction through Nerve and DNA  

Microsoft Academic Search

The aim of the present study was to analyse electric resistivity at different ambient temperatures between 300 to 20K in the frog sciatic nerve and salmon sperm DNA. When the electrical contacts were leaned just into the sciatic nerve, an increase of the sciatic nerve resistivity was observed for 240 K < T < 300 K and a rise of

H. Abdelmelek; A. El-May; Ben Hamouda; M. Ben Salem; J. M. Pequignot; M. Sakly

2003-01-01

247

Peripheral nerve complications following burn injury  

SciTech Connect

The involvement of peripheral nerves in burn injury is not common, but when nerves are involved, prompt therapeutic intervention is necessary to avoid increased morbidity. Aside from the direct effects of the trauma, the burn team must anticipate dangerously excessive edema from circumferential burns, and avoid secondary nerve damage from inappropriate splinting, exercises or traction.

Salisbury, R.E.; Dingeldein, G.P.

1982-03-01

248

Isolated cranial nerve palsies in multiple sclerosis  

PubMed Central

During a 10 year period 24 patients with definite multiple sclerosis with isolated cranial nerve palsies were studied (third and fourth nerve: one patient each, sixth nerve: 12 patients, seventh nerve: three patients, eighth nerve: seven patients), in whom cranial nerve palsies were the presenting sign in 14 and the only clinical sign of an exacerbation in 10 patients. MRI was carried out in 20 patients and substantiated corresponding brainstem lesions in seven patients (third nerve: one patient, sixth nerve: four patients, eighth nerve: two patients). Additional abnormal findings of electro-oculography, or masseter reflex, or blink reflex, or combinations of these were found in 20 patients and interpreted in favour of a brainstem lesion at the level of the respective cranial nerve. In 11 of 14 patients with isolated cranial nerve palsies as the presenting sign of multiple sclerosis, dissemination in space was documented by MRI, and in the remaining three by evoked potentials. In patients with multiple sclerosis with isolated cranial nerve palsies, MRI is the most sensitive method of documenting dissemination in space and electrophysiological testing the most sensitive at disclosing brainstem lesions.?? PMID:9408116

Thomke, F.; Lensch, E.; Ringel, K.; Hopf, H. C.

1997-01-01

249

A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors  

PubMed Central

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

250

A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.  

PubMed

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

251

Anatomical variation: median nerve formation - a case vignette.  

PubMed

Variations in the arrangement and distribution of brachial plexus and its branches in the infraclavicular part are common and have been reported by several investigators since the 19th century. These variations are significant for the neurologists, surgeons, anesthetists and the anatomists. During routine anatomical dissection of the right axilla and infraclavicular region of a 45-year-old male cadaver, the medial root of the median nerve was found to receive a supplementary branch from the medial aspect of the terminal portion of the lateral cord of brachial plexus and the branch was passing infront of the axillary artery from lateral to medial side. The median nerve was formed by joining of the lateral and medial roots from the lateral and medial cords of brachial plexus, infront of brachial artery, lower down, at the junction of upper one-third and lower two-third of the arm, instead in the axilla. This variation could be one of the cause of pressure symptom which occurs on the axillary artery and also the injury which occurs on the lateral cord or upstream to the lateral cord, which may sometimes lead to an unexpected presentation of weakness of forearm flexors and thenar muscles. PMID:25120965

Bala, Anju; Sinha, Pranoti; Tamang, Binod Kumar; Sarda, Rohit Kumar

2014-06-01

252

Anatomical Variation: Median Nerve Formation – A Case Vignette  

PubMed Central

Variations in the arrangement and distribution of brachial plexus and its branches in the infraclavicular part are common and have been reported by several investigators since the 19th century. These variations are significant for the neurologists, surgeons, anesthetists and the anatomists. During routine anatomical dissection of the right axilla and infraclavicular region of a 45-year-old male cadaver, the medial root of the median nerve was found to receive a supplementary branch from the medial aspect of the terminal portion of the lateral cord of brachial plexus and the branch was passing infront of the axillary artery from lateral to medial side. The median nerve was formed by joining of the lateral and medial roots from the lateral and medial cords of brachial plexus, infront of brachial artery, lower down, at the junction of upper one-third and lower two-third of the arm, instead in the axilla. This variation could be one of the cause of pressure symptom which occurs on the axillary artery and also the injury which occurs on the lateral cord or upstream to the lateral cord, which may sometimes lead to an unexpected presentation of weakness of forearm flexors and thenar muscles. PMID:25120965

Sinha, Pranoti; Tamang, Binod Kumar; Sarda, Rohit Kumar

2014-01-01

253

The Optical Stretcher Nerve Regeneration  

E-print Network

!"# $ %& ' "!((! )# The Optical Stretcher Nerve Regeneration Cells as Optical Fibres Novel Imaging-throughput cell analysis method for cancer diagnosis and stem cell sorting. The deformability of cells) and a cancerous cellhealthy (left) and a cancerous cell (right). The cancerous cell is more(right). The cancerous

Steiner, Ullrich

254

The Root Pressure Phenomenon  

ERIC Educational Resources Information Center

Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

Marsh, A. R.

1972-01-01

255

Using Square Roots  

ERIC Educational Resources Information Center

This article describes techniques which enable the user of a comparatively simple calculator to perform calculations of cube roots, nth roots, trigonometric, and inverse trigonometric functions, logarithms, and exponentials. (DT)

Wilson, William Wynne

1976-01-01

256

Functional Reinnervation of the Canine Bladder after Spinal Root Transection and Immediate End-on-End Repair  

PubMed Central

The goal of this study was to transect and immediately repair ventral roots, selected by their ability to stimulate bladder contraction, to assess the feasibility of bladder reinnervation in a canine model. Brain-derived neurotrophic factor (BDNF) was delivered via an osmotic pump (0.5 or 5 mg/mL) to a cuff surrounding the reanastomosis site to the two root bundles on one side. Electrodes were implanted bilaterally immediately proximal to the site of surgical reanastomosis. Results were compared to four root-intact, control animals that also received bilateral electrode implantation. At 6–12 months post-surgery, five of eight nerve transected and repaired animals showed increased pressure and bladder emptying during electrical stimulation of the repaired ventral roots contralateral to the BDNF delivery side. Nerve tracing studies one year postoperatively determined the repaired roots to be S1 and S2 and showed regrowth of axons from the spinal cord to nerve sites proximal to the repair site and to the bladder, and the presence of neurofilament-labeled axons growing across the ventral root repair site. In conclusion, transected ventral and dorsal roots in the sacral spine can be repaired and are capable of functionally reinnervating the urinary bladder. This feasibility study paves the way for future studies utilizing other more proximal motor nerves to bypass the transection site for bladder reinnervation. PMID:16866625

RUGGIERI, MICHAEL R.; BRAVERMAN, ALAN S.; D’ANDREA, LINDA; SIMPKISS, BERNADETTE; KOZIN, SCOTT H.; PONTARI, MICHEL A.; BETZ, RANDALL; BARBE, MARY F.

2012-01-01

257

BLACK ROOT ROT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Black Root Rot Prepared by G. S. Abawi, Revised by L.E. Hanson Black root rot is caused by Thielaviopsis basicola (syn. Chalara elegans). The pathogen is widely distributed, can infect more than 130 plant species in 15 families, and causes severe black root rot diseases in ornamentals and crops suc...

258

SYNAPTIC INHIBITION IN AN ISOLATED NERVE CELL  

PubMed Central

Following the preceding studies on the mechanisms of excitation in stretch receptor cells of crayfish, this investigation analyzes inhibitory activity in the synapses formed by two neurons. The cell body of the receptor neuron is located in the periphery and sends dendrites into a fine muscle strand. The dendrites receive innervation through an accessory nerve fiber which has now been established to be inhibitory. There exists a direct peripheral inhibitory control mechanism which can modulate the activity of the stretch receptor. The receptor cell which can be studied in isolation was stimulated by stretch deformation of its dendrites or by antidromic excitation and the effect of inhibitory impulses on its activity was analyzed. Recording was done mainly with intracellular leads inserted into the cell body. 1. Stimulation of the relatively slowly conducting inhibitory nerve fiber either decreases the afferent discharge rate or stops impulses altogether in stretched receptor cells. The inhibitory action is confined to the dendrites and acts on the generator mechanism which is set up by stretch deformation. By restricting depolarization of the dendrites above a certain level, inhibition prevents the generator potential from attaining the "firing level" of the cell. 2. The same inhibitory impulse may set up a postsynaptic polarization or a depolarization, depending on the resting potential level of the cell. The membrane potential at which the inhibitory synaptic potential reverses its polarity, the equilibrium level, may vary in different preparations. The inhibitory potentials increase as the resting potential is displaced in any direction from the inhibitory equilibrium. 3. The inhibitory potentials usually rise to a peak in about 2 msec. and decay in about 30 msec. After repetitive inhibitory stimulation a delayed secondary polarization phase has frequently been seen, prolonging the inhibitory action. Repetitive inhibitory excitation may also be followed by a period of facilitation. Some examples of "direct" excitation by the depolarizing action of inhibitory impulses are described. 4. The interaction between antidromic and inhibitory impulses was studied. The results support previous conclusions (a) that during stretch the dendrites provide a persisting "drive" for the more central portions of the receptor cell, and (b) that antidromic all-or-none impulses do not penetrate into the distal portions of stretch-depolarized dendrites. The "after-potentials" of antidromic impulses are modified by inhibition. 5. Evidence is presented that inhibitory synaptic activity increases the conductance of the dendrites. This effect may occur in the absence of inhibitory potential changes. PMID:13252239

Kuffler, Stephen W.; Eyzaguirre, Carlos

1955-01-01

259

2028 OPTICS LETTERS / Vol. 29, No. 17 / September 1, 2004 Noncontact measurement of nerve displacement  

E-print Network

motion in cells and other weakly scattering samples. © 2004 Optical Society of America OCIS codes: 120. Laser Doppler vibrometry,5 speckle vi- brometry,6 and laser feedback interferometry7 are sensitive noise in the Michelson interfer- ometer. The use of low-coherence (broadband) light permits depth

Seung, Sebastian

260

Displacement Based Seismic Design Criteria  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

Costello, J.F.; Hofmayer, C.; Park, Y.J.

1999-03-29

261

Polybenzimidazoles via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W. (inventor); Hergenrother, Paul M. (inventor); Smith, Joseph G., Jr. (inventor)

1995-01-01

262

Polybenzimidazoles Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

1997-01-01

263

DISPLACEMENT BASED SEISMIC DESIGN CRITERIA  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

HOFMAYER,C.H.

1999-03-29

264

Variable delivery, fixed displacement pump  

DOEpatents

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01

265

Polyimidazoles via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

Connell, John W. (inventor); Hergenrother, Paul M. (inventor)

1992-01-01

266

Displaceable Gear Torque Controlled Driver  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr. (Inventor)

1997-01-01

267

VAGUS NERVE STIMULATION REGULATES HEMOSTASIS IN SWINE  

PubMed Central

The central nervous system regulates peripheral immune responses via the vagus nerve, the primary neural component of the cholinergic anti-inflammatory pathway. Electrical stimulation of the vagus nerve suppresses pro-inflammatory cytokine release in response to endotoxin, I/R injury, and hypovolemic shock and protects against lethal hypotension. To determine the effect of vagus nerve stimulation on coagulation pathways, anesthetized pigs were subjected to partial ear resection before and after electrical vagus nerve stimulation. We observed that electrical vagus nerve stimulation significantly decreased bleeding time (pre–electrical vagus nerve stimulation = 1033 ± 210 s versus post–electrical vagus nerve stimulation = 585 ± 111 s; P < 0.05) and total blood loss (pre–electrical vagus nerve stimulation = 48.4 ± 6.8 mL versus post–electrical vagus nerve stimulation = 26.3 ± 6.7 mL; P < 0.05). Reduced bleeding time after vagus nerve stimulation was independent of changes in heart rate or blood pressure and correlated with increased thrombin/antithrombin III complex generation in shed blood. These data indicate that electrical stimulation of the vagus nerve attenuates peripheral hemorrhage in a porcine model of soft tissue injury and that this protective effect is associated with increased coagulation factor activity. PMID:19953009

Czura, Christopher J.; Schultz, Arthur; Kaipel, Martin; Khadem, Anna; Huston, Jared M.; Pavlov, Valentin A.; Redl, Heinz; Tracey, Kevin J.

2010-01-01

268

Nerve conduction studies in early tuberculoid leprosy  

PubMed Central

Context: Hansen's disease is a chronic illness; besides involving skin and peripheral nerves, it affects multiple organs. Nerve involvement is always present in leprosy, and it may be present much before the patient manifests clinically. Aims: To assess nerve conduction parameters in thickened and contralateral non-thickened nerves in early tuberculoid leprosy Materials and Methods: Fifty new untreated male patients with tuberculoid and borderline tuberculoid leprosy in the age group of 15-50 years with thickened peripheral nerves on one side were included in the study. Nerve conduction studies consisting of sensory and motor velocity (NCV), distal latencies, and amplitude were carried out on thickened ulnar, common peroneal, and posterior tibial nerves and contralateral normal nerves. Statistical Analysis Used: Mean values along with coefficient of variation were obtained for various parameters. These were compared with normal values of the control population. P value was used to verify statistical significance. Results: Nerve conduction parameters were deranged in most of the thickened nerves. Sensory parameters were affected early in the disease process. Conclusion: Additional parameters are required to assess nerve damage in early cases, where it is more in slow conducting fibers (average velocity fibers). Change in conduction velocity may not be marked; this calls for the measurement of fast fibers separately because potentials recorded are mainly from myelinated fibers. PMID:25593812

Vashisht, Deepak; Das, Arjun Lal; Vaishampayan, Sanjeev S; Vashisht, Surbhi; Joshi, Rajneesh

2014-01-01

269

Prostanoid receptor EP1 and Cox-2 in injured human nerves and a rat model of nerve injury: a time-course study  

PubMed Central

Background Recent studies show that inflammatory processes may contribute to neuropathic pain. Cyclooxygenase-2 (Cox-2) is an inducible enzyme responsible for production of prostanoids, which may sensitise sensory neurones via the EP1 receptor. We have recently reported that while macrophages infiltrate injured nerves within days of injury, they express increased Cox-2-immunoreactivity (Cox-2-IR) from 2 to 3 weeks after injury. We have now investigated the time course of EP1 and Cox-2 changes in injured human nerves and dorsal root ganglia (DRG), and the chronic constriction nerve injury (CCI) model in the rat. Methods Tissue sections were immunostained with specific antibodies to EP1, Cox-2, CD68 (human macrophage marker) or OX42 (rat microglial marker), and neurofilaments (NF), prior to image analysis, from the following: human brachial plexus nerves (21 to 196 days post-injury), painful neuromas (9 days to 12 years post-injury), avulsion injured DRG, control nerves and DRG, and rat CCI model tissues. EP1 and NF-immunoreactive nerve fibres were quantified by image analysis. Results EP1:NF ratio was significantly increased in human brachial plexus nerve fibres, both proximal and distal to injury, in comparison with uninjured nerves. Sensory neurones in injured human DRG showed a significant acute increase of EP1-IR intensity. While there was a rapid increase in EP1-fibres and CD-68 positive macrophages, Cox-2 increase was apparent later, but was persistent in human painful neuromas for years. A similar time-course of changes was found in the rat CCI model with the above markers, both in the injured nerves and ipsilateral dorsal spinal cord. Conclusion Different stages of infiltration and activation of macrophages may be observed in the peripheral and central nervous system following peripheral nerve injury. EP1 receptor level increase in sensory neurones, and macrophage infiltration, appears to precede increased Cox-2 expression by macrophages. However, other methods for detecting Cox-2 levels and activity are required. EP1 antagonists may show therapeutic effects in acute and chronic neuropathic pain, in addition to inflammatory pain. PMID:16393343

Durrenberger, Pascal F; Facer, Paul; Casula, Maria A; Yiangou, Yiangos; Gray, Roy A; Chessell, Iain P; Day, Nicola C; Collins, Sue D; Bingham, Sharon; Wilson, Alex W; Elliot, David; Birch, Rolfe; Anand, Praveen

2006-01-01

270

Heanng Rewarch, 37 (1988) 47-52 Responses from the brainstem at the entrance of the eighth nerve  

E-print Network

Heanng Rewarch, 37 (1988) 47-52 Elsevier 47 HRR 01146 Responses from the brainstem at the entrance) and the lateral brainstem near the root entry zone of N VIII to contralateral click stimulation in patients recorded from the lateral surface of the brainstem near the entrance of the eighth nerve, and consisted

O'Toole, Alice J.

271

Facial nerve demyelination and vascular compression are both needed to induce facial hyperactivity: A study in rats  

Microsoft Academic Search

Summary It is generally assumed that hemifacial spasm (HFS) is caused by vascular compression of the facial nerve at the root exit zone (REZ), but the mechanism for the development of HFS is not known. Evidence has been previously presented that the signs of HFS are caused by hyperactivity of the facial motonucleus that is caused by the irritation to

A. Kuroki; A. R. Møller

1994-01-01

272

Identifying motor and sensory myelinated axons in rabbit peripheral nerves by histochemical staining for carbonic anhydrase and cholinesterase activities  

NASA Technical Reports Server (NTRS)

Carbonic anhydrase (CA) and cholinesterase (CE) histochemical staining of rabbit spinal nerve roots and dorsal root ganglia demonstrated that among the reactive myeliated axons, with minor exceptions, sensory axons were CA positive and CE negative whereas motor axons were CA negative and CE positive. The high specificity was achieved by adjusting reaction conditions to stain subpopulations of myelinated axons selectively while leaving 50 percent or so unstained. Fixation with glutaraldehyde appeared necessary for achieving selectivity. Following sciatic nerve transection, the reciprocal staining pattern persisted in damaged axons and their regenerating processes which formed neuromas within the proximal nerve stump. Within the neuromas, CA-stained sensory processes were elaborated earlier and in greater numbers than CE-stained regenerating motor processes. The present results indicate that histochemical axon typing can be exploited to reveal heterogeneous responses of motor and sensory axons to injury.

Riley, Danny A.; Sanger, James R.; Matloub, Hani S.; Yousif, N. John; Bain, James L. W.

1988-01-01

273

The border between the central and the peripheral nervous system in the cat cochlear nerve: a light and scanning electron microscopical study.  

PubMed

The transition between the central (CNS) and peripheral nervous system (PNS) in cranial and spinal nerve roots, referred to here as the CNS-PNS border, is of relevance to nerve root disorders and factors that affect peripheral-central regeneration. Here, this border is described in the cat cochlear nerve using light microscopical sections, and scanning electron microscopy of the CNS-PNS interfaces exposed by fracture of the nerve either prior to or following critical point drying. The CNS-PNS border represents an abrupt change in type of myelin, supporting elements, and vascularization. Because central myelin is formed by oligodendrocytes and peripheral myelin by Schwann cells, the myelinated fibers are as a rule equipped with a node of Ranvier at the border passage. The border is shallower and smoother in cat cochlear nerve than expected from other nerves, and the borderline nodes are largely in register. The loose endoneurial connective tissue of the PNS compartment is closed at the border by a compact glial membrane, the mantle zone, of the CNS compartment. The mantle zone is penetrated by the nerve fibers, but is otherwise composed of astrocytes and their interwoven processes like the external limiting membrane of the brain surface with which it is continuous. The distal surface of the mantle zone is covered by a fenestrated basal lamina. Only occasional vessels traverse the border. From an anatomical point of view, the border might be expected to be a weak point along the cochlear nerve and thus vulnerable to trauma. In mature animals, the CNS-PNS border presents a barrier to regrowth of regenerating nerve fibers and to invasion of the CNS by Schwann cells. An understanding of this region in the cochlear nerve is therefore relevant to head injuries that lead to hearing loss, to surgery on acoustic Schwannomas, and to the possibility of cochlear nerve regeneration. PMID:21447373

Osen, Kirsten K; Furness, David N; Hackney, Carole M

2011-07-01

274

Reciprocation, Square Root, Inverse Square Root, and Some Elementary Functions  

E-print Network

Reciprocation, Square Root, Inverse Square Root, and Some Elementary Functions Using Small with the computation of reciprocals, square roots, inverse square roots, and some elementary functions using small/number of multipliers and compare with other related methods. Index TermsÐReciprocal, square root, inverse square root

Muller, Jean-Michel

275

Cranial nerves XIII and XIV: nerves in the shadows  

PubMed Central

It has been known for over a century that these cranial nerves exist, and that they are not typographical errors nor a sensational event reported in the medical literature. A number of scientific articles on anatomy highlight how textbooks on descriptive anatomy do not always consider variables such as differences related to the geographical areas where people live, and these differences do exist. This is an important concept not only for surgeons, but also for all medical professionals who use manual techniques when treating their patients, ie, osteopaths, chiropractors, physiotherapists, and other manual therapists. This paper highlights the latest developments regarding these cranial nerves, offering at the same time some ideas for further reflection when looking at clinical scenarios that appear to bear little relationship to each other. Inclusion of these concepts in everyday anamnesis is encouraged. PMID:23516138

Bordoni, Bruno; Zanier, Emiliano

2013-01-01

276

Mapping the entire human corneal nerve architecture  

PubMed Central

We developed an approach to generate a three-dimensional map that facilitates the assessment of epithelial nerve density in different corneal areas to define aging and gender influence on human corneal nerve architecture. Twenty-eight fresh human eyes from 14 donors of different ages were studied. Corneal nerves were stained and consecutive images acquired with a fluorescence microscope, recorded at the same plane, and merged for viewing the complete epithelial and stromal nerve architecture. After whole mount examination, the same cornea was also used for transection. Stromal nerves entered the cornea in a radial pattern, subsequently dividing into smaller branches. Some branches connected at the center of the stroma, but most penetrated upward into the epithelium. No differences were observed between nerve densities in the four corneal quadrants. Epithelial innervation in the limbal and most of the peripheral area was supplied by a superficial network surrounding the limbal area. Central epithelial nerves were supplied by branches of the stromal nerve network. Epithelial nerve density and terminal numbers were higher in the center of the cornea, rather than the periphery. There were no differences in epithelial nerve density between genders, but there was a progressive nerve density reduction concomitant with aging, mainly in eye samples of donors 70-years of age and older. The modified technique of tissue preparation used for this study allowed for observation of new nerve structure features and, for the first time, provided a complete view of the human corneal nerve architecture. Our study reveals that aging decreases the number of central epithelial nerve terminals, and increases the presence of irregular anomalies beneath the basal layer. PMID:20650270

He, Jiucheng; Bazan, Nicolas G.; Bazan, Haydee E.P.

2010-01-01

277

Changes induced by peripheral nerve injury in the morphology and nanomechanics of sensory neurons  

NASA Astrophysics Data System (ADS)

Peripheral nerve injury in vivo promotes a regenerative growth in vitro characterized by an improved neurite regrowth. Knowledge of the conditioning injury effects on both morphology and mechanical properties of live sensory neurons could be instrumental to understand the cellular and molecular mechanisms leading to this regenerative growth. In the present study, we use differential interference contrast microscopy, fluorescence microscopy and atomic force microscopy (AFM) to show that conditioned axotomy, induced by sciatic nerve injury, does not increase somatic size of sensory neurons from adult mice lumbar dorsal root ganglia but promotes the appearance of longer and larger neurites and growth cones. AFM on live neurons is also employed to investigate changes in morphology and membrane mechanical properties of somas of conditioned neurons following sciatic nerve injury. Mechanical analysis of the soma allows distinguishing neurons having a regenerative growth from control ones, although they show similar shapes and sizes.

Benzina, Ouafa; Szabo, Vivien; Lucas, Olivier; Saab, Marie-belle; Cloitre, Thierry; Scamps, Frédérique; Gergely, Csilla; Martin, Marta

2013-06-01

278

Deceased expression of prostatic acid phosphatase in primary sensory neurons after peripheral nerve injury  

PubMed Central

Prostatic acid phosphatase (PAP) is expressed in nociceptive dorsal root ganglion (DRG) neurons and functions as an ectonucleotidase that dephosphorylates extracellular adenosine monophosphate (AMP) to adenosine to suppress pain via activating A1-adenosine receptor (A1R) in dorsal spinal cord. However, the effect of peripheral nerve injury on the expression of PAP has not been reported until now. In the present study we found that PAP expression in DRG neurons is significantly decreased from the 2nd day after peripheral nerve injury and reaches the bottom at the 14th. In addition, intrathecal PAP injection can reduce mechanical allodynia induced by spared nerve injury. Our findings suggest that the decrease of PAP is involved in pathophysiological mechanisms of neuropathic pain.

Huang, Bo; Li, Xia; Zhu, Xiao-Chun; Lu, Yi-Sheng

2014-01-01

279

Myelinated sensory and alpha motor axon regeneration in peripheral nerve neuromas  

NASA Technical Reports Server (NTRS)

Histochemical staining for carbonic anhydrase and cholinesterase (CE) activities was used to analyze sensory and motor axon regeneration, respectively, during neuroma formation in transected and tube-encapsulated peripheral nerves. Median-ulnar and sciatic nerves in the rodent model permitted testing whether a 4 cm greater distance of the motor neuron soma from axotomy site or intrinsic differences between motor and sensory neurons influenced regeneration and neuroma formation 10, 30, and 90 days later. Ventral root radiculotomy confirmed that CE-stained axons were 97% alpha motor axons. Distance significantly delayed axon regeneration. When distance was negligible, sensory axons grew out sooner than motor axons, but motor axons regenerated to a greater quantity. These results indicate regeneration differences between axon subtypes and suggest more extensive branching of motor axons within the neuroma. Thus, both distance from injury site to soma and inherent motor and sensory differences should be considered in peripheral nerve repair strategies.

Macias, M. Y.; Lehman, C. T.; Sanger, J. R.; Riley, D. A.

1998-01-01

280

The Sihler staining study of the infraorbital nerve and its clinical complication.  

PubMed

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement. PMID:25329852

Yang, Hun-Mu; Won, Sung-Yoon; Lee, Young-Il; Kim, Hee-Jin; Hu, Kyung-Seok

2014-11-01

281

Combination of Acellular Nerve Graft and Schwann Cells-Like Cells for Rat Sciatic Nerve Regeneration  

PubMed Central

Objective. To investigate the effect of tissue engineering nerve on repair of rat sciatic nerve defect. Methods. Forty-five rats with defective sciatic nerve were randomly divided into three groups. Rats in group A were repaired by acellular nerve grafts only. Rats in group B were repaired by tissue engineering nerve. In group C, rats were repaired by autogenous nerve grafts. After six and twelve weeks, sciatic nerve functional index (SFI), neural electrophysiology (NEP), histological and transmission electron microscope observation, recovery ratio of wet weight of gastrocnemius muscle, regenerated myelinated nerve fibers number, nerve fiber diameter, and thickness of the myelin sheath were measured to assess the effect. Results. After six and twelve weeks, the recovery ratio of SFI and wet weight of gastrocnemius muscle, NEP, and the result of regenerated myelinated nerve fibers in groups B and C were superior to that of group A (P < 0.05), and the difference between groups B and C was not statistically significant (P > 0.05). Conclusion. The tissue engineering nerve composed of acellular allogenic nerve scaffold and Schwann cells-like cells can effectively repair the nerve defect in rats and its effect was similar to that of the autogenous nerve grafts. PMID:25114806

Gao, Songtao; Zheng, Yan; Cai, Qiqing; Deng, Zhansheng; Yao, Weitao; Wang, Jiaqiang; Wang, Xin; Zhang, Peng

2014-01-01

282

An improved displacement damage monitor LED  

Microsoft Academic Search

A frequency-domain technique for measuring carrier lifetime in GaAs light-emitting-diode (LED) displacement damage monitors capable of high sensitivity and repeatability is developed. Applications of this technique that take advantage of the high sensitivity of this method, including the measurement of the threshold energy for lattice displacement in GaAs, are described. The measured minimum electron energy for displacement damage was 270±15

A. L. Barry; R. Maxseiner; R. Wojcik; M. A. Briere; D. Braeunig

1990-01-01

283

Displacement of crude oil by carbon dioxide  

E-print Network

that passed through the core. Seeson and Ortloff conducted a laboratory study in which they investigated the oil recovery from displacing some high and low viscosity crudes from linear sandstone models. A 400 cp Ada crude oil was displaced from linear... Topedo sandstone and a 6 cp Loudon crude oil was displaced from linear models of Weiler sand- stone at 70 F and at about 1000 psi by water propelled carbon dioxide slugs. They found that the displacement technique was more efficient than waterflooding...

Omole, Olusegun

2012-06-07

284

Feasibility of Nerve Stimulator as a Supplemental Aid for Lumbar Transforaminal Epidural Block  

PubMed Central

Background The purpose of this study was to evaluate the clinical feasibility of an electric nerve stimulator in a lumbar transforaminal epidural block. Methods Using an electric nerve stimulator, transforaminal epidural blocks were performed in 105 segments of 49 patients who presented with lower back pain with radiating pain to lower extremities. The contrast medium was injected to delineate the nerve root after positioning an insulated needle at the intervertebral foramen under fluoroscopic guidance. Then, the nerve root was electrically stimulated with the insulated needle to confirm whether or not the same radiating pain was evoked. Results Of the 105 foraminal segments, the same radiating pain was evoked at 0.5 mAh in 47 segments (44.8%), at 1.0 mAh in 22 (21.0%), at 1.5 mAh in 3 (2.9%), at 2.0 mAh in 15 (14.3%), at 2.5 mAh in 4 (3.8%), and at 3.0 mAh in 5 (4.8%). No response was observed in 9 segments (8.6%). The fluoroscopy revealed successful positioning of the needle in the patients with an evoked radiating pain over 2.0 mAh. The visual analogue scale (VAS) obtained for pain improved from a mean of 7.5 to 2.7 after the block (p = 0.001). In the 9 cases without response to electrical stimulation, the patients showed an improvement on VAS from 7.8 to 3.4 (p= 0.008) also. Conclusions A nerve stimulator can help to predict the accuracy of needle positioning as a supplemental aid for a successful lumbar transforaminal epidural block. It is sufficient to initiate a proper stimulation amplitude of the nerve at 2 mAh. PMID:25177459

Kim, Dae Hee; Lim, Chae Hyun; Heo, Ju Yeong; Jang, Young Jae

2014-01-01

285

Assesing tree-root & soil interaction using pull-out test apparatus  

NASA Astrophysics Data System (ADS)

Knowing in situ root strength provides a better understanding of the responses of tree root systems against external loads. Root pullout devices are used to record these strengths and can be expressed in two ways: pullout force, which is a direct output from the load cell (measured in pounds) or pullout stress, which is the pullout force divided by root cross section area (measured in pounds per square in.). Pullout tests show not only the possible tensile strength of a tree root, but also the interaction between the tree root and the surrounding geological materials. After discussion with engineers from the University of Nottingham-Trent, the U.S. Army Engineer Research and Development Center (ERDC) constructed a root pullout apparatus with some modifications. These modifications included using a T-System configuration at the base of an aluminum frame instead of a diagonal rod and varying the size of the clamp placed around the tested root. The T-System is placed in front of the root perpendicular to the root path. In the ERDC pullout device, the root was pulled directly without a lever system. A string pot was used to measure displacement when the root was pulled. The device is capable of pulling tree roots with a diameter of up to 2.5 in. and a maximum load of 5000 lbs. Using this device, ERDC conducted field operations in Portland, Oregon; Burlington, Washington; and Albuquerque, New Mexico, on Oregon ash, alder, maple, and cedar trees. In general, pullout tests were conducted approximately 60 deg around the tree selected for the tests. The location of a test depended on the availability of a root near the ground surface. A backhoe was used to remove soil around the tree to locate roots. Before the root was secured in a clamp, root diameter was measured and recorded, and the root was photographed. The tree species, dip angle and dip direction of the root, root location with respect to the tree, tree location, dates, weather, and soil type were also recorded. When the test begins the load cell and displacement transducers immediately started recording the measurements, and the measurements are stored on a laptop computer. The hydraulic pump controls the rate of loading for a relatively slow pulling displacement rate of 0.08 in./sec. Failure occurred when the root breaks or was pulled out of the soil. Maximum forces and root failure location were noted, as well as any additional observations during and after the test. In the ERDC tests, root diameters (root with bark) ranged between 0.7 and 2.33 in., the pullout force was between 86 and 3513 lb, and the pullout stress was between 56 and 2645 psi. ERDC recorded three different types of tree-root failures: pure root tensile failure, bonding between root and soil failure, and a combination of the two. In tensile failure, a root breaks abruptly and the force versus displacement curve usually shows a steep slope, and there is no residual strength. In a bonding failure, the force versus displacement curve shows a gentler slope, and there is residual strength. A combined failure mode may also occur. For pullout tests conducted for the ERDC research, the combined mode failure was the most prevalent failure mechanism.

Wibowo, J.; Corcoran, M. K.; Kala, R.; Leavell, D.

2011-12-01

286

The nerves around the shoulder.  

PubMed

Neuropathies of the shoulder are considered to be entrapment syndromes. They are relatively common, accounting for about 2% of cases of sport-related shoulder pain. Many instances involve suprascapular neuropathy, but the clinical diagnosis is often delayed because of nonspecific symptoms. Classically, EMG is the gold standard investigation but MRI currently reveals muscular abnormality in 50% of cases. Muscle edema, the most characteristic symptom, is nonspecific. In general, the topography of edema, the presence of a lesion compressing the nerve and clinical history contribute to the diagnosis. Although atrophy and fatty degeneration may persist after the disappearance of edema, they are rarely symptomatic. The main differential diagnosis is Parsonage-Turner syndrome. Evidence of a cyst pressing on a nerve may prompt puncture-infiltration guided by ultrasonography or CT-scan. PMID:21546184

Blum, Alain; Lecocq, Sophie; Louis, Matthias; Wassel, Johnny; Moisei, Andreea; Teixeira, Pedro

2013-01-01

287

Mechanisms of nerve injury in leprosy.  

PubMed

All patients with leprosy have some degree of nerve involvement. Perineural inflammation is the histopathologic hallmark of leprosy, and this localization may reflect a vascular route of entry of Mycobacterium leprae into nerves. Once inside nerves, M leprae are ingested by Schwann cells, with a wide array of consequences. Axonal atrophy may occur early in this process; ultimately, affected nerves undergo segmental demyelination. Knowledge of the mechanisms of nerve injury in leprosy has been greatly limited by the minimal opportunities to study affected nerves in man. The nine-banded armadillo provides the only animal model of the pathogenesis of M leprae infection. New tools available for this model enable the study and correlation of events occurring in epidermal nerve fibers, dermal nerves, and nerve trunks, including neurophysiologic parameters, bacterial load, and changes in gene transcription in both neural and inflammatory cells. The armadillo model is likely to enhance understanding of the mechanisms of nerve injury in leprosy and offers a means of testing proposed interventions. PMID:25432810

Scollard, David M; Truman, Richard W; Ebenezer, Gigi J

2015-01-01

288

Effects of melatonin on peripheral nerve regeneration.  

PubMed

In the available literature, there are thousands of studies on peripheral nerve regeneration using many nerves of several animals at different ages with various types of lesions and different methods of evaluation at certain time of follow-up. Despite many experimental data and clinical observations, there is still no ideal treatment method enhancing peripheral nerve regeneration. In clinical practice, various types of surgical nerve repair techniques do not frequently result in complete recovery due to neuroma formation, lipid peroxidative damage, ischemia and other factors. Recently, a number of neuroscientists demonstrated that pineal neurohormone melatonin (MLT) has an effect on the morphologic features of the nerve tissue, suggesting its neuroprotective, free radical scavenging, antioxidative, and analgesic effects in degenerative diseases of peripheral nerves. At present, it is widely accepted that MLT has a useful effect on axon length and sprouting after traumatic events to peripheral nerves. Our studies using various experimental injury models clearly suggest positive effects of MLT on the number of axons, thickness of myelin sheath by inhibition of collagen accumulation and neuroma formation following traumatic events to peripheral nerves, myelination of developing peripheral nerve after intrauterine ethanol exposure. Nevertheless, further experimental and randomized controlled clinical studies are vital to identify the clinical use of MLT hormone. This is an overview of recent patents and current literature in terms of the effects of MLT on peripheral nerve regeneration based on a critical analysis of electrophysiological, biochemical and light and electron microscopic findings, in addition to functional observations. PMID:22074585

Turgut, Mehmet; Kaplan, Süleyman

2011-05-01

289

Polybenzoxazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Hergenrother, Paul M. (inventor); Connell, John W. (inventor); Smith, Joseph G., Jr. (inventor)

1993-01-01

290

Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects  

PubMed Central

It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were cally observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. Masson's trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cells on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects. PMID:25206536

Biazar, Esmaeil; Keshel, Saeed Heidari; Pouya, Majid; Rad, Hadi; Nava, Melody Omrani; Azarbakhsh, Mohammad; Hooshmand, Shirin

2013-01-01

291

Interspecific Variation in Root Growth in Cymbopogon in Root Boxes  

Microsoft Academic Search

Interspecific variation for root growth and development was studied in palmarosa (Cymbopogon martinii), lemongrass (Cymbopogon flexuosus), and citronella (Cymbopogon winterianus) grown in root boxes in a glass house. Cymbopogon winterianus had highest root biomass and deep root growth (between 30–100 cm soil depth) plus a greater total root-to-shoot ratio and deep root-to-shoot ratio than the other species. This root development

N. K. Srivastava; R. Kumar; D. Dixit

2003-01-01

292

Displaced Homemakers: Vo-Tech Workshop Guide.  

ERIC Educational Resources Information Center

Written for displaced homemaker programs in vocational-technical schools, this curriculum contains material designed so that instructors can prepare student manuals appropriate to almost any educational support situation for displaced homemakers. An overview provides information on special needs groups, curriculum use, and resources and sample…

Peltier, Wanda Jo

293

High displacement ceramic metal composite actuators (moonies)  

Microsoft Academic Search

The two most common type of piezoelectric actuators are the multilayer actuator with internal electrodes and the cantilevered bimorph actuator. A new type of composite ceramic actuator is the multilayered multistacked moonie (multi-multi moonie). Normal multilayer actuators produce a large generative force, but only a small displacement. Conversely, bimorphs produce large displacements but the forces are very small. The moonie

Aydin Dogan; Qichang Xu; Katsuhiko Onitsuka; Shoko Yoshikawa; Kenji Uchino; Robert E. Newnham

1994-01-01

294

Video Games, Adolescents, and the Displacement Effect  

ERIC Educational Resources Information Center

The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

Fisher, Carla Christine

2012-01-01

295

Stress-free displacement control of structures  

Microsoft Academic Search

Summary. The theorem on the unique decomposition of eigenstrain provides the tool to construct prescribed displacements inside and (or) at the surface of a linear elastic body in two novel ways (e.g., in connection with shape control). The first approach applies Maysel’s formula and renders the linear relationship between nodal displacements and impotent eigenstrain in discrete or discretized systems. The

Y. Nyashin; V. Lokhov; F. Ziegler

2005-01-01

296

BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS  

EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

297

Management of an Extremely Displaced Maxillary Canine  

Microsoft Academic Search

Case Report: Aligning a displaced maxillary canine into the den- tal arch is one of the most complicated problems in orthodontics. In cases of extremely high displacement, the tooth is frequently removed surgically. Because of the upper canines' significance to dental esthetics and functional occlusion, such a decision is a very serious one. This case report illustrates the treatment of

Torsten Grande; Annemarie Stolze; Heiko Goldbecher

2005-01-01

298

Saphenous nerve innervation of the medial ankle  

PubMed Central

Background The distal saphenous nerve is commonly known to provide cutaneous innervation of the medial side of the ankle and distally to the base of the great toe. We hypothesize that the saphenous nerve innervates the periosteum of the medial malleolus and joint capsule. Methods Five fresh limbs were dissected and the saphenous nerve was traced distally with magnification. The medial malleolus, talus, and soft tissue were fixed in formaldehyde, decalcified, and embedded in paraffin and sectioned. Histologic slides were then prepared using S100 antibody nerve stains. Results Histologic slides were examined and myelinated nerves could be observed within the medial capsule and periosteum in all the specimens. Conclusion We have demonstrated that the saphenous nerve innervates the periosteum of the medial malleolus and joint capsule. PMID:23630434

Clendenen, Steven R; Whalen, Joseph L

2013-01-01

299

Congenital optic nerve pit in trisomy 18.  

PubMed

The authors report the first case of trisomy 18 associated with a clinically detectable optic nerve pit. A female infant with a birth weight of 2,150 g was born by cesarean section to a healthy 40-year-old woman at 38 weeks of gestation. Trisomy 18 had been diagnosed by prenatal genetic testing. Ophthalmologic examination was remarkable for bilateral narrowed palpebral fissures with punctal agenesis, corectopic pupils without reaction to light, bilateral inferior peripapillary retinochoroidal hypopigmentation, and significant optic nerve cupping in the left eye with associated temporal optic nerve pit. It has generally been accepted that optic nerve pits are a congenital anomaly. However, the pathophysiological background of optic nerve pits remains unclear and controversial. This is the first clinical and photographic documentation of an optic nerve pit in a neonate and in Edwards syndrome. PMID:24601433

Villegas, Victor M; Chang, Jonathan S; Hess, Ditte J; Berrocal, Audina M

2013-01-01

300

Congenital optic nerve pit in trisomy 18.  

PubMed

The authors report the first case of trisomy 18 associated with a clinically detectable optic nerve pit. A female infant with a birth weight of 2,150 g was born by cesarean section to a healthy 40-year-old woman at 38 weeks of gestation. Trisomy 18 had been diagnosed by prenatal genetic testing. Ophthalmologic examination was remarkable for bilateral narrowed palpebral fissures with punctal agenesis, corectopic pupils without reaction to light, bilateral inferior peripapillary retinochoroidal hypopigmentation, and significant optic nerve cupping in the left eye with associated temporal optic nerve pit. It has generally been accepted that optic nerve pits are a congenital anomaly. However, the pathophysiological background of optic nerve pits remains unclear and controversial. This is the first clinical and photographic documentation of an optic nerve pit in a neonate and in Edwards syndrome. PMID:23739588

Villegas, Victor M; Chang, Jonathan S; Hess, Ditte J; Berrocal, Audina M

2013-01-01

301

Spontaneous intraneural hematoma of the sural nerve.  

PubMed

Symptomatic intraneural hemorrhage occurs rarely. It presents with pain and/or weakness in the distribution following the anatomic innervation pattern of the involved nerve. When a purely sensory nerve is affected, the symptoms can be subtle. We present a previously healthy 36-year-old female who developed an atraumatic, spontaneous intraneural hematoma of her sural nerve. Sural dysfunction was elicited from the patient's history and physical examination. The diagnosis was confirmed with magnetic resonance imaging, and surgical decompression provided successful resolution of her preoperative symptoms. To our knowledge, this entity has not been reported previously. Our case highlights the importance of having a high index of suspicion for nerve injury or compression in patients whose complaints follow a typical peripheral nerve distribution. Prior studies have shown that the formation of intraneural hematoma and associated compression of nerve fibers result in axonal degeneration, and surgical decompression decreases axonal degeneration and aids functional recovery. PMID:25311865

Richardson, Shawn S; McLawhorn, Alexander S; Mintz, Douglas N; DiCarlo, Edward F; Weiland, Andrew J

2015-04-01

302

An unusual cause of radial nerve palsy.  

PubMed

Neurapraxia frequently occurs following traction injury to the nerve intraoperatively, leading to radial nerve palsy which usually recovers in 5-30 weeks. In our case, we had operated a distal one-third of humeral shaft fracture and fixed it with 4.5 mm limited contact dynamic compression plate. The distal neurovascular status of the limb was assessed postoperatively in the recovery room and was found to be intact and all the sensory-motor functions of the radial nerve were normal. On the second postoperative day, following the suction drain removal and dressing, patient developed immediate radial nerve palsy along with wrist drop. We reviewed the literature and found no obvious cause for the nerve palsy and concluded that it was due to traction injury to the radial nerve while removing the suction drain in negative pressure. PMID:24889983

Agrawal, Hemendra Kumar; Khatkar, Vipin; Garg, Mohit; Singh, Balvinder; Jaiman, Ashish; Sharma, Vinod Kumar

2014-06-01

303

TRPA1 induced in sensory neurons contributes to cold hyperalgesia after inflammation and nerve injury  

PubMed Central

Cold hyperalgesia is a well-documented symptom of inflammatory and neuropathic pain; however, the underlying mechanisms of this enhanced sensitivity to cold are poorly understood. A subset of transient receptor potential (TRP) channels mediates thermosensation and is expressed in sensory tissues, such as nociceptors and skin. Here we report that the pharmacological blockade of TRPA1 in primary sensory neurons reversed cold hyperalgesia caused by inflammation and nerve injury. Inflammation and nerve injury increased TRPA1, but not TRPM8, expression in tyrosine kinase A–expressing dorsal root ganglion (DRG) neurons. Intrathecal administration of anti–nerve growth factor (anti-NGF), p38 MAPK inhibitor, or TRPA1 antisense oligodeoxynucleotide decreased the induction of TRPA1 and suppressed inflammation- and nerve injury–induced cold hyperalgesia. Conversely, intrathecal injection of NGF, but not glial cell line–derived neurotrophic factor, increased TRPA1 in DRG neurons through the p38 MAPK pathway. Together, these results demonstrate that an NGF-induced TRPA1 increase in sensory neurons via p38 activation is necessary for cold hyperalgesia. Thus, blocking TRPA1 in sensory neurons might provide a fruitful strategy for treating cold hyperalgesia caused by inflammation and nerve damage. PMID:16110328

Obata, Koichi; Katsura, Hirokazu; Mizushima, Toshiyuki; Yamanaka, Hiroki; Kobayashi, Kimiko; Dai, Yi; Fukuoka, Tetsuo; Tokunaga, Atsushi; Tominaga, Makoto; Noguchi, Koichi

2005-01-01

304

Nicotine facilitates reinnervation of phenol-injured perivascular adrenergic nerves in the rat mesenteric resistance artery.  

PubMed

Nicotine has been shown to have neuroprotective and neurotrophic actions in the central nervous system. To elucidate the peripheral neurotrophic effects of nicotine, we determined whether nicotine affected the reinnervation of mesenteric perivascular nerves following a topical phenol treatment. A topical phenol treatment was applied to the superior mesenteric artery proximal to the abdominal aorta in Wistar rats. We examined the immunohistochemistry of the distal small arteries 7 days after the treatment. The topical phenol treatment markedly reduced the density of tyrosine hydroxylase (TH)-LI and calcitonin gene-related peptide (CGRP)-LI fibers in these arteries. The administration of nicotine at a dose of 3mg/kg/day (1.5mg/kg/injection, twice a day), but not once a day or its continuous infusion using a mini-pump significantly increased the density of TH-LI nerves without affecting CGRP-LI nerves. A pretreatment with nicotinic acetylcholine receptor antagonists hexamethonium, mecamylamine, and methyllycaconitine, but not dextrometorphan, canceled the TH-LI nerve reinnervation induced by nicotine. Nicotine significantly increased NGF levels in the superior cervical ganglia (SCG) and mesenteric arteries, but not in the dorsal root ganglia, and also up-regulated the expression of NGF receptors (TrkA) in the SCG, which were canceled by hexamethonium. These results suggested that nicotine exhibited neurotrophic effects that facilitated the reinnervation of adrenergic TH-LI nerves by activating ?7 nicotinic acetylcholine receptor and NGF in the SCG. PMID:25514605

Takatori, Shingo; Fujiwara, Hidetoshi; Hagimori, Kenta; Hashikawa-Hobara, Narumi; Yokomizo, Ayako; Takayama, Fusako; Tangsucharit, Panot; Ono, Nobufumi; Kawasaki, Hiromu

2015-02-01

305

Surgical technique of vagus nerve-preserving gastrectomy with D2 lymphadenectomy for gastric cancer.  

PubMed

Preservation of the vagus nerve in curative gastrectomy for gastric cancer is important to maintain postoperative quality of life. We developed a vagus nerve-preserving gastrectomy with D2 dissection for patients with early gastric cancer and for selected patients with T2 cancer. Following lymph node dissection along the left gastric artery, the root of the left gastric artery was isolated and divided. The coeliac branch was followed retrogradely, and the posterior gastric branches were cut at their origins. The hepatic branch was also preserved. A total of 136 patients, including 27 cases of T2 cancer, underwent the vagus nerve-preserving gastric operation, and surgical anatomy of the coeliac branch was studied. In 110 cases, variations in the course of the coeliac branch were classified into three types according to its relationship with the left gastric artery: close to the artery (43 cases, 39.1%), intermediate (47 cases, 42.7%) and away from the artery (20 cases, 18.2%). In 115 patients who underwent vagus nerve-preserving distal gastrectomy (n = 93) or pylorus-preserving gastrectomy (n = 22), the postoperative bodyweight was 95.6 +/- 5.2% of the preoperative bodyweight, and the incidence of gallstone formation was 1.8% (2 of 113). A D2 dissection comparable with conventional D2 gastrectomy could be carried out using the vagus nerve-preserving technique. The coeliac branch could be preserved regardless of its anatomy, resulting in improvements in postoperative quality of life. PMID:18269482

Ando, Shigemitsu; Tsuji, Hideki

2008-03-01

306

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation  

SciTech Connect

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)] [University Hospital of Strasbourg (France)

2013-12-15

307

Plant root exudates  

Microsoft Academic Search

Conclusions  Although the quantities of organic compounds exuding from roots is not large, seldom exceeding 0.4% of the carbon photosynthesized,\\u000a they do exert a very strong influence on the soil microorganisms and may be significant in affecting plant nutrient availability.\\u000a There is evidence that exudates from the roots of some plants are toxic to roots of neighboring plants and to the

Albert D. Rovira

1969-01-01

308

[Value of gadolinium magnetic resonance imaging of the lumbosacral roots in acute polyradiculoneuritis].  

PubMed

Four patients with acute inflammatory polyradiculoneuropathy were evaluated with MRI. In 3 of 4 cases, gadolinium enhancement was observed in the nerve roots of cauda equina, on frontal and horizontal slices. This enhancement was correlated with the severity of the clinical picture and the cerebrospinal-fluid inflammatory protein concentration and supports the inflammatory nature of this forms of acute polyradiculoneuropathy. PMID:7481378

Fayolle, H; Creisson, E; André, N; Billiar, T; Baudoin, N; Soichot, P; Giroud, M; Dumas, R

1995-04-01

309

Imunoreactivity of zinc transporter 7 (ZNT7) in mouse dorsal root ganglia  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the present study, we showed for the first time the localization of ZNT7 immunoreactivity in the mouse dorsal root ganglion (DRG) by means of immunohistochemistry and confocal laser scanning microscopy. Our results revealed that ZNT7 immunoreactivity was abundantly expressed in the nerve cells of...

310

Bilateral fibrolipomatous hamartoma of the median nerve with macrocheiria and late-onset nerve entrapment syndrome.  

PubMed

The case of a 46-year-old man is reported who presented with an extraordinary constellation of fibrolipomatous hamartomas of the right ulnar and both median nerves, with a right-sided giant hand ("macrocheiria") due to enlarged bones and subcutaneous tissue, and unusual late manifestation of nerve entrapment at the right wrist. Magnetic resonance imaging of the hypertrophied nerves disclosed large nerve fascicles surrounded by fibrous tissue, which allowed preoperative diagnosis. PMID:9572249

Meyer, B U; Röricht, S; Schmitt, R

1998-05-01

311

An ecohydrological framework for grass displacement by woody plants in savannas  

NASA Astrophysics Data System (ADS)

the past several decades, woody plants have been encroaching into grasslands around the world. This transition in plant dominance is often explained as a state shift in bistable ecosystem dynamics induced by fire-vegetation feedbacks. These feedbacks occur when woody plants are able to displace grasses because of their better access to soil water and light. On the other hand, grasses can displace woody plants because of their ability to increase fire frequency and of the higher susceptibility of woody plants to fire-induced mortality. In this study, we present an ecohydrological framework to investigate the displacement of grasses by woody plants. Considering the effect of lateral root spread and of soil water and light limitations, we found that woody plant encroachment can substantially suppress grass production even without the presence of grazers. Bistable dynamics emerge as a result of the grass-fire feedback for a wide range of rainfall conditions, fire susceptibility, and woody plant growth rates.

Yu, Kailiang; D'Odorico, Paolo

2014-03-01

312

Raman microspectroscopy for visualization of peripheral nerves  

NASA Astrophysics Data System (ADS)

The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery is essential for improving quality of life of patients. To preserve peripheral nerves, detection of ne peripheral nerves that cannot be identi ed by human eye or under white light imaging is necessary. In this study, we sought to provide a proof-of-principle demonstration of a label-free detection technique of peripheral nerve tissues against adjacent tissues that employs spontaneous Raman microspectroscopy. A line-illumination confocal Raman microscope was used for the experiment. A laser operating at the wavelength of 532 nm was used as an excitation laser light. We obtained Raman spectra of peripheral nerve, brous connective tissue, skeletal muscle, blood vessel, and adipose tissue of Wistar rats, and extracted speci c spectral features of peripheral nerves and adjacent tissues. By applying multivariate image analysis, peripheral nerves were clearly detected against adjacent tissues without any preprocessing neither xation nor staining. These results suggest the potential of the Raman spectroscopic observation for noninvasive and label-free nerve detection, and we expect this method could be a key technique for nerve-sparing surgery.

Minamikawa, Takeo; Harada, Yoshinori; Koizumi, Noriaki; Takamatsu, Tetsuro

2013-02-01

313

Ventral nerve cord in Phoronopsis harmeri larvae.  

PubMed

The nervous system organization is considered a phylogenetically important character among metazoans. The phylum Phoronida is included in a supraphyletic taxon known as Lophotrochozoa. Many lophotrochozoans possess a metameric ventral nerve cord as adults or larvae. Phoronids do not exhibit external metamery either as larvae or as adults. The current study describes the ventral nerve cord in the young larva of Phoronopsis harmeri. This structure is apparent both in the serotonergic and FMRF-amidergic nervous system in young larvae. The ventral nerve cord extends from the mouth to the tentacular ridge. Both serotonergic and FMRF-amidergic components consist of two ventrolateral nerves, each with several unipolar neurons. The ventrolateral nerves connect to each other by means of thin repetitive transversal nerves ("commissures"). The abundance of neurons and nerves in the epidermis of the oral field of actinotrocha larva likely reflects the importance of this area in collection of food particles. The ventral nerve cords of the actinotrocha and the metatrochophore differ in their positions with respect to ciliated bands: the cord is located between the preoral and postoral ciliated bands in the actinotrocha but between the postoral ciliated band and telotroch in the metatrochophore. The presence of the ventral nerve cord, which contains repetitive elements (neurons and "commissures"), in the early development of P. harmeri may recapitulate some stages of nervous system development during phoronid phylogeny. The larval nervous system does not contain nervous centers under the tentacular ridge that can correlate with the catastrophic metamorphosis and unique body plan of phoronids. PMID:21898789

Temereva, Elena N

2012-01-15

314

Facial nerve paralysis following pediatric cardiac surgery.  

PubMed

A newborn female diagnosed with transposition of the great vessels with restrictive ventricular septal defect presented left facial peripheral nerve paralysis following anatomical surgery correction (arterial switch) by cardiopulmonary bypass. We have not found any causal factor either in the anesthesia or postoperative period. The electromyogram presented signs of peripheral nerve impairment, and the cerebral echography and electroencephalogram were normal. The facial nerve paralysis was almost recovered seven weeks after surgery. This is the first pediatric patient reported with peripheral facial nerve paralysis after cardiac surgery. PMID:8869372

Alcaraz, A; Lopez-Herce, J; Castro, P; Bustinza, A; Moroto, C

1995-09-01

315

Endoscopic ulnar nerve release and transposition.  

PubMed

The most common site of ulnar nerve compression is within the cubital tunnel. Surgery has historically involved an open cubital tunnel release with or without transposition of the nerve. A comparative study has demonstrated that endoscopic decompression is as effective as open decompression and has the advantages of being less invasive, utilizing a smaller incision, producing less local symptoms, causing less vascular insult to the nerve, and resulting in faster recovery for the patient. Ulnar nerve transposition is indicated with symptomatic ulnar nerve instability or if the ulnar nerve is located in a "hostile bed" (eg, osteophytes, scarring, ganglions, etc.). Transposition has previously been performed as an open procedure. The authors describe a technique of endoscopic ulnar nerve release and transposition. Extra portals are used to allow retractors to be inserted, the medial intermuscular septum to be excised, cautery to be used, and a tape to control the position of the nerve. In our experience this minimally invasive technique provides good early outcomes. This report details the indications, contraindications, surgical technique, and rehabilitation of the endoscopic ulnar nerve release and transposition. PMID:24296546

Morse, Levi P; McGuire, Duncan T; Bain, Gregory I

2014-03-01

316

Nerve conduction in Frogs and Humans  

NSDL National Science Digital Library

These exercises are taken from a vertebrate physiology course, and use either a human subject or a dissected frog, thus providing relatively simply alternatives that may suit your needs. Nerve conduction velocity can be measured in the frog sciatic nerve with recordings of the biphasic action potential on the outside of the nerve trunk. Absolute and relative refractory periods can also be determined. Conduction velocity in the human can be obtained from electromyograms taken from the fourth and fifth fingers following stimulation of the ulnar nerve.

Elizabeth Vizsolyi (Univ. of British Columbia; )

1988-06-13

317

Ossifying fibrolipomatous hamartoma of the ulnar nerve.  

PubMed

An ossified fibrolipomatous epineural hamartoma limited to the right ulnar nerve and some of its branches and extending from the elbow distally is described in a 5-year-old boy who complained of pain in the right hand. Such extensive involvement of the ulnar nerve is unusual; moreover, metaplastic bone is rarely present in the more common fibrolipomatous hamartoma of the median nerve. Increased awareness of this entity is necessary to avoid sacrifice of large nerves that may be included in the lesion. PMID:3137556

Drut, R

1988-01-01

318

Ginsenoside Rg1 promotes peripheral nerve regeneration in rat model of nerve crush injury  

Microsoft Academic Search

Searching for effective drugs which are capable of promoting nerve regeneration after nerve injuries has gained extensive attention. Ginsenoside Rg1 (GRg1) is one of the bioactive compounds extracted from ginseng. GRg1 has been shown to be neuroprotective in many in vitro studies, which raises the possibility of using GRg1 as a neuroprotective agent after nerve injuries. However, such a possibility

Junxiong Ma; Wenxian Li; Ruifeng Tian; Wei Lei

2010-01-01

319

Regeneration of perivascular adrenergic innervation in rat tibial nerve after nerve crush.  

PubMed

Adrenergic innervation of blood vessels in the rat tibial nerve during degeneration and regeneration was studied using the formaldehyde-induced fluorescence method. The left sciatic nerve was crushed with suture threads to produce a 4-mm length of crushed nerve. At 1, 3, 7, 14, 28, 56 and 84 days after nerve crush, degenerative and regenerative changes in the nerve were verified using light microscopy. At each time point, adrenergic innervation was examined in epi-perineurial whole mount and nerve cross-section preparations. One day after nerve crush, fluorescence of adrenergic nerve fibers in the endoneurium was absent. Fluorescent adrenergic nerve fibers reappeared in the endoneurium at day 56 and reached the control density by 84 days. In the epi-perineurium, adrenergic innervation of small and medium-size arterioles was absent at 3 days, in large arterioles at 7 days. At 56 days, all epi-perineurial arterioles were reinnervated by a faint, sparse adrenergic network, which reached the control density at 84 days. The results suggest that adrenergic innervation in the rat peripheral nerve is lost during nerve degeneration, but recovers when the nerve has regenerated. PMID:1713392

Koistinaho, J; Wadhwani, K C; Balbo, A; Rapoport, S I

1991-01-01

320

A simple model of radial nerve injury in the rhesus monkey to evaluate peripheral nerve repair  

PubMed Central

Current research on bone marrow stem cell transplantation and autologous or xenogenic nerve transplantation for peripheral nerve regeneration has mainly focused on the repair of peripheral nerve defects in rodents. In this study, we established a standardized experimental model of radial nerve defects in primates and evaluated the effect of repair on peripheral nerve injury. We repaired 2.5-cm lesions in the radial nerve of rhesus monkeys by transplantation of autografts, acellular allografts, or acellular allografts seeded with autologous bone marrow stem cells. Five months after surgery, regenerated nerve tissue was assessed for function, electrophysiology, and histomorphometry. Postoperative functional recovery was evaluated by the wrist-extension test. Compared with the simple autografts, the acellular allografts and allografts seeded with bone marrow stem cells facilitated remarkable recovery of the wrist-extension functions in the rhesus monkeys. This functional improvement was coupled with radial nerve distal axon growth, a higher percentage of neuron survival, increased nerve fiber density and diameter, increased myelin sheath thickness, and increased nerve conduction velocities and peak amplitudes of compound motor action potentials. Furthermore, the quality of nerve regeneration in the bone marrow stem cells-laden allografts group was comparable to that achieved with autografts. The wrist-extension test is a simple behavioral method for objective quantification of peripheral nerve regeneration. PMID:25206757

Wang, Dong; Huang, Xijun; Fu, Guo; Gu, Liqiang; Liu, Xiaolin; Wang, Honggang; Hu, Jun; Yi, Jianhua; Niu, Xiaofeng; Zhu, Qingtang

2014-01-01

321

Upregulation of Nuclear Factor of Activated T-Cells by Nerve Injury Contributes to Development of Neuropathic Pain  

PubMed Central

Nerve injury induces long-term changes in gene expression in the nociceptive circuitry and can lead to chronic neuropathic pain. However, the transcriptional mechanism involved in neuropathic pain is poorly understood. Nuclear factor of activated T-cells (NFATc) is a transcriptional factor regulated by the Ca2+-dependent protein phosphatase calcineurin. In this study, we determined nerve injury–induced changes in the expression of NFATc1–c4 in the dorsal root ganglia (DRG) and spinal cords and their role in the development of neuropathic pain. The mRNA of NFATc1–c4 was detected in the rat DRG and dorsal spinal cord. Nerve injury transiently elevated NFATc1–c3 mRNA levels and persistently increased NFATc4 and C-C chemokine receptor type 2 (CCR2) mRNA levels in the DRG. However, NFATc1–c4 mRNA levels in the spinal cord were not altered significantly by nerve injury. Nerve injury also significantly increased the protein level of dephosphorylated NFATc4 in the DRG. Intrathecal injection of the specific NFATc inhibitor 11R-VIVIT or the calcineurin inhibitor FK-506 (tacrolimus) early after nerve injury significantly attenuated the development of tactile allodynia. In addition, treatment with FK-506 or 11R-VIVIT significantly reduced the mRNA levels of NFATc4 and CCR2 but not large-conductance Ca2+-activated K+ channels, in the DRG after nerve injury. Our findings suggest that peripheral nerve injury causes a time-dependent change in NFATc1–c4 expression in the DRG. Calcineurin-NFATc–mediated expression of pronociceptive cytokines contributes to the transition from acute to chronic pain after nerve injury. PMID:23386250

Cai, You-Qing; Chen, Shao-Rui

2013-01-01

322

Development and Evolution of Character Displacement  

PubMed Central

Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement’s mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions. PMID:22257002

Pfennig, David W.; Pfennig, Karin S.

2012-01-01

323

Total displacement functions for SiC  

NASA Astrophysics Data System (ADS)

Numerical solutions for the displacement functions in SiC are determined from the coupled integro-differential equations governing the total number of type- j atoms displaced in the collision cascade initiated by a primary knock-on atom (PKA) of type- i and energy E. Atomic scattering cross sections based on either the inverse power law screening potentials or the Ziegler, Biersack, and Littmark (ZBL) universal screening potential are used in the calculation of the displacement functions. The electronic stopping powers used in the calculations are either derived from the LSS and Bethe-Bloch theories or generated from the SRIM-96 electronic stopping power data base. The displacement functions determined using LSS/Bethe-Bloch electronic stopping powers are 25 to 100% larger than the displacement functions determined using the electronic stopping powers generated by SRIM-96. The total number of displaced atoms determined numerically for each PKA type, based on ZBL scattering cross sections and SRIM-96 electronic stopping powers, is in excellent agreement, over the entire range of PKA energies (10 eV to 10 MeV), with the total number of displacements determined by full cascade Monte Carlo simulations using the TRIM code in SRIM-96.

Weber, W. J.; Williford, R. E.; Sickafus, K. E.

1997-04-01

324

Irrational Square Roots  

ERIC Educational Resources Information Center

If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?

Misiurewicz, Michal

2013-01-01

325

The Roots of Literacy.  

ERIC Educational Resources Information Center

This review of research with children aged two to six on their reading, writing, and oral language development speaks of five roots of a tree of literate life that require nourishment in the soil of a written language environment. The roots discussed are the development of print awareness in situational contexts, the development of print awareness…

Goodman, Yetta M.

326

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Electrical peripheral nerve stimulator. 868...Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator...

2014-04-01

327

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Electrical peripheral nerve stimulator. 868...Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator...

2010-04-01

328

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Electrical peripheral nerve stimulator. 868...Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator...

2011-04-01

329

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Electrical peripheral nerve stimulator. 868...Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator...

2013-04-01

330

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Electrical peripheral nerve stimulator. 868...Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator...

2012-04-01

331

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Nerve conduction velocity measurement device. 882...Diagnostic Devices § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is...

2011-04-01

332

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Nerve conduction velocity measurement device. 882...Diagnostic Devices § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is...

2012-04-01

333

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Nerve conduction velocity measurement device. 882...Diagnostic Devices § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is...

2013-04-01

334

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 false Nerve conduction velocity measurement device. 882...Diagnostic Devices § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is...

2014-04-01

335

Palsies of Cranial Nerves That Control Eye Movement  

MedlinePLUS

... Disorders 4 Palsies of Cranial Nerves That Control Eye Movement These disorders involve paralysis of one of the cranial nerves that control eye movement (the 3rd, 4th, or 6th nerve), impairing the ...

336

Detergent-free Decellularized Nerve Grafts for Long-gap Peripheral Nerve Reconstruction  

PubMed Central

Background: Long-gap peripheral nerve defects arising from tumor, trauma, or birth-related injuries requiring nerve reconstruction are currently treated using nerve autografts and nerve allografts. Autografts are associated with limited supply and donor-site morbidity. Allografts require administration of transient immunosuppressants, which has substantial associated risks. To overcome these limitations, we investigated the use of detergent-free decellularized nerve grafts to reconstruct long-gap nerve defects in a rodent model and compared it with existing detergent processing techniques. Methods: Nerve grafts were harvested from the sciatic nerves of 9 donor rats. Twenty-four recipient rats were divided into 4 groups (6 animals per group): (1) nerve grafts (NG, positive control), (2) detergent-free decellularized (DFD) grafts, (3) detergent decellularized grafts, and (4) silicone tube conduits (negative control). Each recipient rat had a 3.5-cm graft or conduit sutured across a sciatic nerve transection injury. All animals were harvested at 12 weeks postimplantation for functional muscle analysis and nerve histomorphometry. Results: Histomorphometry results indicated maximum growth in NG when compared with other groups. DFD and detergent decellularized groups showed comparable regeneration at 12 weeks. Silicone tube group showed no regeneration as expected. Muscle force data indicated functional recovery in NG and DFD groups only. Conclusions: This study describes a detergent-free nerve decellularization technique for reconstruction of long-gap nerve injuries. We compared DFD grafts with an established detergent processing technique and found that DFD nerve grafts are successful in promoting regeneration across long-gap peripheral nerve defects as an alternative to existing strategies. PMID:25426384

Vasudevan, Srikanth; Huang, Jiying; Botterman, Barry; Matloub, Hani S.; Keefer, Edward

2014-01-01

337

Length-displacement scaling and fault growth  

NASA Astrophysics Data System (ADS)

Following an earthquake in a fault zone, commonly the co-seismic rupture length and the slip are measured. Similarly, in a structural analysis of major faults, the total fault length and displacement are measured when possible. It is well known that typical rupture length-slip ratios are generally orders of magnitude larger than typical fault length-displacement ratios. So far, however, most of the measured co-seismic ruptures and faults have been from different areas and commonly hosted by rocks of widely different mechanical properties (which have strong effects on these ratios). Here we present new results on length-displacement ratios from 7 fault zones in Holocene lava flows on the flanks of the volcano Etna (Italy), as well as 10 co-seismic rupture length-slips, and compare them with fault data from Iceland. The displacement and slip data from Etna are mostly from the same fault zones and hosted by rocks with largely the same mechanical properties. For the co-seismic ruptures, the average length is 3657 m, the average slip 0.31 m, and the average length-slip ratio 19,595. For the faults, the average length is 6341 m, the average displacement 73 m, and the average length-displacement ratio 130. Thus, the average rupture-slip ratio is about 150-times larger than the average length-displacement ratio. We propose a model where the differences between the length-slip and the length-displacement ratios can be partly explained by the dynamic Young's modulus of a fault zone being 101-2-times greater than its static modulus. In this model, the dynamic modulus controls the length-slip ratios whereas the static modulus controls the length-displacement ratio. We suggest that the common aseismic slip in fault zones is partly related to adjustment of the short-term seismogenic length-slip ratios to the long-term length-displacement ratios. Fault displacement is here regarded as analogous to plastic flow, in which case the long-term displacement can be very large so long as sufficient shear stress concentrates in the fault.

Gudmundsson, Agust; De Guidi, Giorgio; Scudero, Salvatore

2013-11-01

338

Arthroscopic treatment of femoral nerve paresthesia caused by an acetabular paralabral cyst.  

PubMed

This report describes a rare case of femoral nerve paresthesia caused by an acetabular paralabral cyst of the hip joint. A 68-year-old woman presented with a 6-month history of right hip pain and paresthesia along the anterior thigh and radiating down to the anterior aspect of the knee. Radiography showed osteoarthritis with a narrowed joint space in the right hip joint. Magnetic resonance imaging showed a cyst with low T1- and high T2-weighted signal intensity arising from a labral tear at the anterior aspect of the acetabulum. The cyst was connected to the joint space and displaced the femoral nerve to the anteromedial side. The lesion was diagnosed as an acetabular paralabral cyst causing femoral neuropathy. Because the main symptom was femoral nerve paresthesia and the patient desired a less invasive procedure, arthroscopic labral repair was performed to stop synovial fluid flow to the paralabral cyst that was causing the femoral nerve paresthesia. After surgery, the cyst and femoral nerve paresthesia disappeared. At the 18-month follow-up, the patient had no recurrence. There have been several reports of neurovascular compression caused by the cyst around the hip joint. To the authors' knowledge, only 3 cases of acetabular paralabral cysts causing sciatica have been reported. The current patient appears to represent a rare case of an acetabular paralabral cyst causing femoral nerve paresthesia. The authors suggest that arthroscopic labral repair for an acetabular paralabral cyst causing neuropathy can be an option for patients who desire a less invasive procedure. PMID:24810828

Kanauchi, Taira; Suganuma, Jun; Mochizuki, Ryuta; Uchikawa, Shinichi

2014-05-01

339

[Capsaicin-sensitive afferents in the vagus nerve].  

PubMed

Vanilloids were shown to interact with over 70% of vagal C-afferents first causing an excitation followed by desensitisation and a lasting destruction of nerve fibres. Capsaicin induces a secretion of some neuropeptides from 10-30% of vagal sensory terminals and therefore serves as a pharmacological tool for testing local "effector function" of primary afferents. Vagal afferents seem to have their own subtype of vanilloid receptors (VR), not completely identical with the VR receptors in the dorsal root ganglia. Considering potentiation of the capsaicin receptors sensitivity by some factors such as local heating, pH, free oxygen radicals, a possible role of the VRs as integrators of chemical and physical components of nociceptive stimuli, is discussed. PMID:11296704

Zolotarev, A D; Nozdrachev, A D

2001-02-01

340

Immediate versus delayed primary nerve repair in the rabbit sciatic nerve  

PubMed Central

It is well known that peripheral nerve injury should be treated immediately in the clinic, but in some instances, repair can be delayed. This study investigated the effects of immediate versus delayed (3 days after injury) neurorrhaphy on repair of transected sciatic nerve in New Zealand rabbits using stereological, histomorphological and biomechanical methods. At 8 weeks after immediate and delayed neurorrhaphy, axon number and area in the sciatic nerve, myelin sheath and epineurium thickness, Schwann cell morphology, and the mechanical property of nerve fibers did not differ obviously. These results indicate that delayed neurorrhaphy do not produce any deleterious effect on sciatic nerve repair. PMID:25206663

Piskin, Ahmet; Altunkaynak, Berrin Zühal; Ç?tlak, Atilla; Sezgin, Hicabi; Yaz?c?, Ozgür; Kaplan, Süleyman

2013-01-01

341

Two-level motor nerve transfer for the treatment of long thoracic nerve palsy.  

PubMed

The authors report a case of long thoracic nerve (LTN) palsy treated with two-level motor nerve transfers of a pectoral fascicle of the middle trunk, and a branch of the thoracodorsal nerve. This procedure resulted in near-total improvement of the winged scapula deformity, and a return of excellent shoulder function. A detailed account of the postoperative physical therapy regimen is included, as this critical component of the favorable result cannot be overlooked. This case establishes the two-level motor nerve transfer as a new option for treating LTN palsy, and demonstrates that nerve transfers should be considered in the therapeutic algorithm of an idiopathic mononeuritis. PMID:21699477

Ray, Wilson Z; Pet, Mitchell A; Nicoson, Michael C; Yee, Andrew; Kahn, Lorna C; Mackinnon, Susan E

2011-10-01

342

Carbon dioxide laser-assisted nerve repair: effect of solder and suture material on nerve regeneration in rat sciatic nerve.  

PubMed

In order to further improve and explore the role of lasers for nerve reconstruction, this study was designed to investigate regeneration of sharply transected peripheral nerves repaired with a CO(2) milliwatt laser in combination with three different suture materials and a bovine albumin protein solder as an adjunct to the welding process. Unilateral sciatic nerve repair was performed in 44 rats. In the laser group, nerves were gently apposed, and two stay sutures (10-0 nylon, 10-0 polyglycolic acid, or 25 microm stainless steel) were placed epi/perineurially. Thereafter, the repair site was fused at 100 mW with pulses of 1.0 s. In the subgroup of laser-assisted nerve repair (LANR), albumen was used as a soldering agent to further reinforce the repair site. The control group consisted of nerves repaired by conventional microsurgical suture repair (CMSR), using 4-6 10-0 nylon sutures. Evaluation was performed at 1 and 6 weeks after surgery, and included qualitative and semiquantitative light microscopy. LANR performed with a protein solder results in a good early peripheral nerve regeneration, with an optimal alignment of nerve fibers and minimal connective tissue proliferation at the repair site. All three suture materials produced a foreign body reaction; the least severe was with polyglycolic acid sutures. CMSR resulted in more pronounced foreign-body granulomas at the repair site, with more connective-tissue proliferation and axonal misalignment. Furthermore, axonal regeneration in the distal nerve segment was better in the laser groups. Based on these results, CO(2) laser-assisted nerve repair with soldering in combination with absorbable sutures has the potential of allowing healing to occur with the least foreign-body reaction at the repair site. Further experiments using this combination are in progress. PMID:12740882

Menovsky, Tomas; Beek, Johan F

2003-01-01

343

An inconvenient truth: treatment of displaced paediatric supracondylar humeral fractures.  

PubMed

The need for emergent management of displaced paediatric supracondylar humeral fractures is being questioned in the literature. Open reduction rates of up to 46% have been reported in the non-emergent management of these injuries. At our institution these fractures are managed as operative emergencies by senior personnel. To examine the ongoing need for this policy we reviewed our results. All patients managed over a five year period with Gartland type IIB or III paeditric supracondylar humeral fractures were identified and a comprehensive chart and radiographic review undertaken. The mean time from injury to fracture reduction and stabilization was 6.6 h. Consultants performed or supervised 90% of cases. Open reduction was necessary in 5% of cases. Complications included a perioperative nerve injury rate of 6% and a superficial pin site infection rate of 3%. This study suggests that, despite the challenge to trauma on-call rostering, the emergency management of these injuries is advantageous to patients in units of our size. Based on the data presented here we continue our practice of emergent management. We suggest that units of a similar size to our own would show a benefit from an analogous policy albeit an inconvenient truth. PMID:22525415

Donnelly, M; Green, C; Kelly, I P

2012-06-01

344

Nerve injury induces a new profile of tactile and mechanical nociceptor input from undamaged peripheral afferents.  

PubMed

Chronic pain after nerve injury is often accompanied by hypersensitivity to mechanical stimuli, yet whether this reflects altered input, altered processing, or both remains unclear. Spinal nerve ligation or transection results in hypersensitivity to mechanical stimuli in skin innervated by adjacent dorsal root ganglia, but no previous study has quantified the changes in receptive field properties of these neurons in vivo. To address this, we recorded intracellularly from L4 dorsal root ganglion neurons of anesthetized young adult rats, 1 wk after L5 partial spinal nerve ligation (pSNL) or sham surgery. One week after pSNL, hindpaw mechanical withdrawal threshold in awake, freely behaving animals was decreased in the L4 distribution on the nerve-injured side compared with sham controls. Electrophysiology revealed that high-threshold mechanoreceptive cells of A-fiber conduction velocity in L4 were sensitized, with a seven-fold reduction in mechanical threshold, a seven-fold increase in receptive field area, and doubling of maximum instantaneous frequency in response to peripheral stimuli, accompanied by reductions in after-hyperpolarization amplitude and duration. Only a reduction in mechanical threshold (minimum von Frey hair producing neuronal activity) was observed in C-fiber conduction velocity high-threshold mechanoreceptive cells. In contrast, low-threshold mechanoreceptive cells were desensitized, with a 13-fold increase in mechanical threshold, a 60% reduction in receptive field area, and a 40% reduction in instantaneous frequency to stimulation. No spontaneous activity was observed in L4 ganglia, and the likelihood of recording from neurons without a mechanical receptive field was increased after pSNL. These data suggest massively altered input from undamaged sensory afferents innervating areas of hypersensitivity after nerve injury, with reduced tactile and increased nociceptive afferent response. These findings differ importantly from previous preclinical studies, but are consistent with clinical findings in most patients with chronic neuropathic pain. PMID:25274350

Boada, M Danilo; Gutierrez, Silvia; Aschenbrenner, Carol A; Houle, Timothy T; Hayashida, Ken-Ichiro; Ririe, Douglas G; Eisenach, James C

2015-01-01

345

Primary spinal intradural extraskeletal Ewing sarcoma mimicking a giant nerve sheath tumor: case report and review of the literature  

PubMed Central

Primary intradural extraskeletal Ewing sarcoma is a very rare form of malignant neoplasm. Only few cases have been reported on the literature. Here, we report a case of a 14-year-old boy who had a chief complaint of pain and tingling in the right lower limb. The patient initially seemed to have a giant nerve sheath tumor but was eventually diagnosed with intradural extraskeletal Ewing sarcoma arising from the nerve roots of the cauda equine. The literature with regard to primary spinal intradural extraskeletal Ewing sarcoma is reviewed.

Zhao, Mingfei; Zhang, Buyi; Liang, Feng; Zhang, Jianmin

2014-01-01

346

Nerve Sprouting and Sudden Cardiac Death  

Microsoft Academic Search

The factors that contribute to the occurrence of sudden cardiac death (SCD) in patients with chronic myocardial infarction (MI) are not entirely clear. The present study tests the hypothesis that augmented sympathetic nerve regeneration (nerve sprouting) increases the probability of ventricular tachycardia (VT), ventricular fibrillation (VF), and SCD in chronic MI. In dogs with MI and complete atrioventricular (AV) block,

Ji-Min Cao; Lan S. Chen; Bruce H. KenKnight; Toshihiko Ohara; Moon-Hyoung Lee; Jerome Tsai; William W. Lai; Hrayr S. Karagueuzian; Paul L. Wolf; Michael C. Fishbein; Peng-Sheng Chen

347

Myoclonus following a Peripheral Nerve Block  

PubMed Central

Myoclonus is an extremely rare perioperative complication following neuraxial anesthesia. It has also been reported to occur due to peripheral nerve lesions. We report a case of self-limiting myoclonus following a routine peripheral nerve block in an otherwise healthy patient. PMID:23936682

Hudson, Arlene J.; Guthmiller, Kevin B.; Hyatt, Marian N.

2013-01-01

348

Maternal anticonvulsants and optic nerve hypoplasia.  

PubMed Central

Seven patients with optic nerve hypoplasia, born of epileptic mothers, are presented. All the mothers took anticonvulsants during pregnancy. The possibility that maternal anticonvulsant therapy may play a role in the genesis of optic nerve hypoplasia is discussed in the light of what is known about the teratogenicity of these agents. Images PMID:415754

Hoyt, C. S.; Billson, F. A.

1978-01-01

349

Occipital nerve stimulation for chronic migraine.  

PubMed

Occipital nerve stimulation may be effective in treating chronic migraine. Six studies, including three double-blind studies, were performed, with five showing evidence of benefit. However, of the three randomized, controlled trials, none has met a primary endpoint successfully. A separate study suggested a benefit for combined supraorbital and greater occipital nerve stimulation. PMID:24474153

Young, William B

2014-02-01

350

Flexible signal generator for facial nerve detection  

Microsoft Academic Search

During surgical intervention on patient face, the facial nerve must be protected. To avoid the risk of its damage, we propose an electronic device that could detect the presence of this nerve. Thanks to its excitability, it was possible therefore to record a noticeable muscular electric reaction on the face. An active stimulating electrode would be placed on the patient

Habib ELKHORCHANI; Hamadi GHARIANI; A. Benhamida; M. Ghorbel

2004-01-01

351

Role of lumbricus extract in the nerve amplification effect during peripheral nerve regeneration  

PubMed Central

Among the methods of the peripheral nerve repair, artificial conduit bridging surgery is superior to epineurium and perineurium neurorrhaphy because of supplying enough space for nerve regeneration. Artificial conduit provides important microenvironment for peripheral nerve regeneration, especially for nerve amplification effect. Amplification phenomenon has been demonstrated in many studies using artificial conduit. When a finer nerve is used as a donor to connect to a distal nerve after injury, the donor nerve regenerates more lateral buds than its own fibers, which grow into distal endoneurial tubes and finally dominate the target organs. In this study, we used artificial conduit to investigate the amplification phenomenon in rats treated with Lumbricus extract as adjuvant treatment. The rats were divided into three groups at random. In the surgical groups, the proximal common peroneal nerve was used as a donor nerve to connect the distal tibial nerve. Rats in the normal group were not performed surgery. Postoperatively, the treatment group was administered Lumbricus extract as adjuvant treatment, while the model group and normal group were not given treatment. The results showed that the nerve conduction velocity, the morphometric measurements, the histological analysis and the amplification ratio in the treatment group were better than in the model group. PMID:25628798

Zhang, Peixun; Wang, Zhiyong; Kou, Yuhui; Han, Na; Xu, Chungui; Yin, Xiaofeng; Wang, Yanhua; Feng, Xue

2014-01-01

352

Micrograting Displacement Sensor with Integrated Electrostatic Actuation  

NASA Astrophysics Data System (ADS)

A high-resolution micro-grating displacement sensor with diffraction-based and integrated electrostatic actuation is proposed and experimentally demonstrated. The Al reflecting membrane is fabricated at the bottom of a silicon moving part and the Au micro-gratings are patterned on a transparent substrate. This structure forms a phase sensitive diffraction grating, providing the displacement sensitivity of the micro-grating interferometer. It shows sensitivity adjustment and self-calibration capabilities with electrostatic actuation. Additional system components include a coherent light source, photodiodes, and required electronics. Experimental results show that the displacement sensor has a sensitivity of about 1.8 mV/nm and a resolution of less than 1 nm in the linear region. This displacement sensor is very promising in the fields requiring high sensitivity, broad dynamic range, and immunity to electromagnetic interference.

Yao, Bao-Yin; Feng, Li-Shuang; Wang, Xiao; Liu, Wei-Fang; Liu, Mei-Hua

2014-07-01

353

REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES  

E-print Network

REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES By TUNG MINH TRAN A THESIS PRESENTED INTRODUCTION.........................................................................1 2 THREE-THREE TENSEGRITY-THREE TENSEGRITY PLATFORMS WITH AN APPLIED EXTERNAL WRENCH....................................... 28 Plücker

Florida, University of

354

Scale model studies of displacement ventilation  

E-print Network

Displacement ventilation is an air conditioning method that provides conditioned air to indoor environments with the goal to improve air quality while reducing energy consumption. This study investigates the performance ...

Okutan, Galip Mehmet

1995-01-01

355

Imaging of auriculotemporal nerve perineural spread  

PubMed Central

Importance: Adenoid cystic carcinomas (ACCs) are relatively rare tumours, notorious for wide local infiltration and perineural spread. Perineural extension commonly occurs along branches of the trigeminal and facial nerves, and its presence represents a poor prognostic factor with implications for treatment approach. Observations: We report the case of a 61-year-old female presenting with worsening left facial numbness and weakness. On magnetic resonance imaging, the patient was found to have perineural spread of a left parotid tumour along the auriculotemporal nerve. There was involvement of the V2 and V3 branches of the trigeminal nerve. An ultrasound-guided biopsy of the mass demonstrated ACC. Conclusions and relevance: The auriculotemporal nerve may serve as a route for tumour spread, particularly in the setting of head and neck malignancy. Moreover, this particular suspicion should be raised when patients with known malignancy experience concomitant trigeminal (V) and facial (VII) nerve dysfunctions. PMID:24282445

Chan, Michael; Dmytriw, Adam A.; Bartlett, Eric; Yu, Eugene

2013-01-01

356

On the terminology of cranial nerves.  

PubMed

The present contribution adopts various points of view to discuss the terminology of the twelve nervi craniales. These are paired nerves and have dual names, terms with Roman ordinal numerals, i.e., the nerves are numbered in the top-to-bottom direction, and descriptive historical names. The time of origin and motivation behind the investigated terms are determined. The majority of terms come from the 17th and 18th centuries. The motivation behind most of them is (a) nerve localization, as this is in conformity with anatomical nomenclature in general, (b) nerve function, and rarely (c) nerve appearance. The occurrence of synonymous names and variants is also a focus of attention. In several cases, reference is made to the process called terminologization, meaning when a certain expression acquires technical meaning and the characteristic/feature of the term. PMID:21724380

Simon, František; Mare?ková-Štolcová, Elena; Pá?, Libor

2011-10-20

357

OCT image segmentation of the prostate nerves  

NASA Astrophysics Data System (ADS)

The cavernous nerves course along the surface of the prostate and are responsible for erectile function. Improvements in identification, imaging, and visualization of the cavernous nerves during prostate cancer surgery may improve nerve preservation and postoperative sexual potency. In this study, 2-D OCT images of the rat prostate were segmented to differentiate the cavernous nerves from the prostate gland. Three image features were employed: Gabor filter, Daubechies wavelet, and Laws filter. The features were segmented using a nearestneighbor classifier. N-ary morphological post-processing was used to remove small voids. The cavernous nerves were differentiated from the prostate gland with a segmentation error rate of only 0.058 +/- 0.019.

Chitchian, Shahab; Weldon, Thomas P.; Fried, Nathaniel M.

2009-08-01

358

Peripheral nerve allografting - why and how?  

PubMed

The authors briefly present the methods of reconstruction of peripheral nerve gaps. Of these methods, the reconstruction with nerve allografts is reviewed mainly in what concerns the ways to achieve host tolerance for the allograft. The authors underline the fact that, for the recipient it is better to suppress the graft antigenicity than to suppress the host immune response. Further, the authors present the most important methods to denaturate a nerve allograft in order to make it nonantigenic and insist upon developing methods that can be used in human beings. The authors conclude that reconstruction of nerve defects with peripheral nerve allografts is a very rewarding method that should be extended in clinical practice. PMID:25375041

B?doiu, S C; Lasc?r, I; Enescu, D M

2014-01-01

359

Peripheral nerve morphogenesis induced by scaffold micropatterning  

PubMed Central

Several bioengineering approaches have been proposed for peripheral nervous system repair, with limited results and still open questions about the underlying molecular mechanisms. We assessed the biological processes that occur after the implantation of collagen scaffold with a peculiar porous microstructure of the wall in a rat sciatic nerve transection model compared to commercial collagen conduits and nerve crush injury using functional, histological and genome wide analyses. We demonstrated that within 60 days, our conduit had been completely substituted by a normal nerve. Gene expression analysis documented a precise sequential regulation of known genes involved in angiogenesis, Schwann cells/axons interactions and myelination, together with a selective modulation of key biological pathways for nerve morphogenesis induced by porous matrices. These data suggest that the scaffold’s microstructure profoundly influences cell behaviors and creates an instructive micro-environment to enhance nerve morphogenesis that can be exploited to improve recovery and understand the molecular differences between repair and regeneration. PMID:24559639

Memon, Danish; Boneschi, Filippo Martinelli; Madaghiele, Marta; Brambilla, Paola; Del Carro, Ubaldo; Taveggia, Carla; Riva, Nilo; Trimarco, Amelia; Lopez, Ignazio D.; Comi, Giancarlo; Pluchino, Stefano; Martino, Gianvito; Sannino, Alessandro; Quattrini, Angelo

2014-01-01

360

Histological assessment in peripheral nerve tissue engineering  

PubMed Central

The histological analysis of peripheral nerve regeneration is one of the most used methods to demonstrate the success of the regeneration through nerve conduits. Nowadays, it is possible to evaluate different parameters of nerve regeneration by using histological, histochemical, immunohistochemical and ultrastructural techniques. The histochemical methods are very sensible and are useful tools to evaluate the extracellular matrix remodeling and the myelin sheath, but they are poorly specific. In contrast, the immunohistochemical methods are highly specific and are frequently used for the identification of the regenerated axons, Schwann cells and proteins associated to nerve regeneration or neural linage. The ultrastructural techniques offer the possibility to perform a high resolution morphological and quantitative analysis of the nerve regeneration. However, the use of a single histological method may not be enough to assess the degree of regeneration, and the combination of different histological techniques could be necessary. PMID:25374585

Carriel, Víctor; Garzón, Ingrid; Alaminos, Miguel; Cornelissen, Maria

2014-01-01

361

Magnetic Resonance Imaging Visualizes Median Nerve Entrapment due to Radius Fracture and Allows Immediate Surgical Release  

PubMed Central

Median nerve entrapment with forearm fracture is rare, and surgical exploration in the early stage is rarely performed. We report the case of a 19-year-old man presenting with severe pain and numbness of the thumb, index, and middle fingers and half of the ring finger along with weakness of abduction and opposition of the thumb after fracture of the radial shaft. These symptoms remained unimproved despite precise closed reduction and cast immobilization. The radius fracture was barely displaced, but complaints were increasing, particularly when the wrist and/or fingers were stretched. This suggested direct involvement of the median nerve at the fracture site, so magnetic resonance imaging (MRI) of the forearm was performed to identify any entrapment. Short tau inversion recovery MRI visualized significant deviation and entrapment of the median nerve at the fracture site. Surgical release of the entrapment was performed immediately, and complaints resolved shortly thereafter. A positive Tinel sign from the palm to the fingertips and recovery of abduction and opposition of the thumb were seen at 6 months postoperatively. This report highlights the utility of MRI for detecting median nerve entrapment at a fracture site, allowing immediate surgical release.

Yanagibayashi, Satoshi; Yamamoto, Naoto; Yoshida, Ryuichi; Sekido, Mitsuru

2015-01-01

362

Effect of Interfacial Tension on Displacement Efficiency  

Microsoft Academic Search

Immiscible displacement tests were performed in a consolidated sandstone core over the interfacial tension range from less than 0.01 dynes\\/cm to 5 dynes\\/cm to better define how interfacial tension (IFT) reduction can lead to increased oil recovery. The data obtained were displacement efficiency at breakthrough vs. IFT for both drainage and imbibition conditions. These tests simulate waterflooding under oil-wet conditions

O. R. Wagner; R. O. Leach

1966-01-01

363

Mechanically amplified large displacement piezoelectric actuators  

Microsoft Academic Search

This paper deals with large displacement actuators based on mechanically amplified movements of pre-stressed piezoelectric disks. The bridge-type amplifier structures were made of laser cut polymer laminates fold to certain geometries to accomplish enhanced displacement of the input translation. Optimization of the lever lengths and their positions were carried out using computer-assisted design (by AutoCAD) and mathematical calculations (by MATLAB).

J. Juuti; K. Kordás; R. Lonnakko; V.-P. Moilanen; S. Leppävuori

2005-01-01

364

Study on optical fiber based displacement sensor  

NASA Astrophysics Data System (ADS)

Fiber optic sensor is commonly used in control and monitoring system for material deformation, strain, temperature, pressure and other industrial process parameters. Fiber optic displacement sensor based on intensity modulation can be designed by using the transmission technique where the intensity gradually changes due to change of detected laser intensity. Previous optical fiber based displacement sensors are constructed using two fibers along with a mirror arrangement or a single optical fiber acting as both transmitter and receiver such as 2X1 fiber couplers. The reported resolution of the system was in the range of 5 ?m-10 ?m. In our present study the displacement sensor composed of a laser source, optical fiber cable, microscope objective and power meter is designed. As in source-fiber coupling geometry, the microscope objective focuses the laser light onto a multimode glass fiber. The other end of the fiber is coupled to a power meter. As the fiber is displaced towards the focused spot, the detected power changes. The displacement resolution of 5 ?m is obtained with this simple setup. In the present paper, the results of theoretical analysis and experimental study of such a simple optical fiber based displacement sensor are presented.

Chakraborty, B.; Sinha, B. K.

2011-10-01

365

Multifunctional Silk Nerve Guides for Axon Outgrowth  

NASA Astrophysics Data System (ADS)

Peripheral nerve regeneration is a critical issue as 2.8% of trauma patients present with this type of injury, estimating a total of 200,000 nerve repair procedures yearly in the United States. While the peripheral nervous system exhibits slow regeneration, at a rate of 0.5 mm -- 9 mm/day following trauma, this regenerative ability is only possible under certain conditions. Clinical repairs have changed slightly in the last 30 years and standard methods of treatment include suturing damaged nerve ends, allografting, and autografting, with the autograft the gold standard of these approaches. Unfortunately, the use of autografts requires a second surgery and there is a shortage of nerves available for grafting. Allografts are a second option however allografts have lower success rates and are accompanied by the need of immunosuppressant drugs. Recently there has been a focus on developing nerve guides as an "off the shelf" approach. Although some natural and synthetic guidance channels have been approved by the FDA, these nerve guides are unfunctionalized and repair only short gaps, less than 3 cm in length. The goal of this project was to identify strategies for functionalizing peripheral nerve conduits for the outgrowth of neuron axons in vitro . To accomplish this, two strategies (bioelectrical and biophysical) were indentified for increasing axon outgrowth and promoting axon guidance. Bioelectrical strategies exploited electrical stimulation for increasing neurite outgrowth. Biophysical strategies tested a range of surface topographies for axon guidance. Novel methods were developed for integrating electrical and biophysical strategies into silk films in 2D. Finally, a functionalized nerve conduit system was developed that integrated all strategies for the purpose of attaching, elongating, and guiding nervous tissue in vitro. Future directions of this work include silk conduit translation into a rat sciatic nerve model in vivo for the purpose of repairing long (> 3 cm) peripheral nerve gaps.

Tupaj, Marie C.

366

NERVE GROWTH FACTOR, NEUROPEPTIDES AND CUTANEOUS NERVES IN ATOPIC DERMATITIS  

PubMed Central

Introduction: Neurogenic components, as neurotrophic factors and neuropeptides, are probably involved in the pathogenesis of atopic dermatitis (AD) with the neuroimmunocutaneous system as they modify the functions of immunoactive cells in the skin. Nerve growth factor (NGF) is the best-characterized member of the neurotrophin family. Both NGF and neuropeptides (NPs) may be associated with the disease pathogenesis. Aim: This study aims to evaluate the plasma level of NGF and NPs in AD patients and correlate them with the disease activity and nerve changes in the skin by electron microscopy. Materials and Methods: Plasma levels of NGF and vasoactive intestinal peptide (+VIP) were measured by an immunoenzymatic assay while plasma levels of calcitonine gene related peptide (CGRP) and neuropeptide Y (NPY) were measured by radioimmunoassay in 30 AD patients in comparison to 10 normal non-atopic controls. Electron microscopic study was done in 10 AD patients. Results: It has been found that there is significant increase of plasma levels of NGF and NPs in AD patients compared with controls. There is a positive correlation between the plasma levels of NGF and disease activity (correlation coefficient = 0.750, P<0.005). There is a significant correlation between the number of Schwann axon complex, evidenced by electron microscopic examination and plasma level of NGF in AD patients. Conclusion: It has been concluded that these neurogenic factors; NGF and NPs modulate the allergic response in AD, probably through interactions with cells of the immune-inflammatory component. NGF might be considered as a marker of the disease activity. PMID:20606880

Hodeib, Abeer; El-Samad, Zeinab Abd; Hanafy, Hesham; El-Latief, Amani Abd; El-bendary, Amal; Abu-Raya, Azza

2010-01-01

367

Tsunami mortality and displacement in Aceh province, Indonesia  

E-print Network

Tsunami mortality and displacement in Aceh province, Indonesia Abdur Rofi, MA Mercy Corps Indonesia, Indonesia, Shannon Doocy, PhD Research Associate, Johns Hopkins Bloomberg School of Public Health, US. Keywords: displacement, internally displaced persons (IDPs), Indonesia, mortality, tsunami Introduction

Scharfstein, Daniel

368

ECOLOGY: How Do Roots Interact?  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Roots actively forage for nutrient hot spots and avoid patches where root densities of competing neighbors are high. Several studies have shown that roots respond to neighboring roots in a very specific manner that depends on the identity of the neighbor. Root extension tends to be greater when roots grow into substrate containing "nonself " roots of a genetically different individual or a detached plant with the same genotype than when "self " roots of the same (physiological and genetic) individual are encountered.

Hans de Kroon (Radboud University;Department of Experimental Plant Ecology, Institute for Water and Wetland Research)

2007-12-07

369

The management of the displaced medial wall in complex acetabular fractures using plates and additional cerclage.  

PubMed

Reduction for displaced quadrilateral plates in complicated acetabular fractures is difficult and requires wide exposure. The purpose of this study is to assess the usefulness of the additional cable in this complicated fracture and to evaluate the potential danger of compressing the superior gluteal artery and nerve with cable application. We evaluated 31 hips (these included 25 hips with fractures of both columns, two posterior wall and column fractures, three anterior column and posterior hemitransverse fractures, and one high T-shaped fracture) with an average six-year follow-up. Clinical outcomes were evaluated using a modification of the Matta grading system and radiographic arthritic grades. We assessed the postoperative clinical outcomes in relation with other variables such as anatomical reduction, delayed operation, seagull sign, and femoral head injuries. We determined whether the superior gluteal artery and nerve were compressed by cerclage with the help of femoral angiography and EMG. Clinical outcomes were graded as very good to excellent for 18 patients, good for five, fair for three ?and poor for five. Preoperative femoral head injury (P = 0.011), a seagull sign (P = 0.001), poor reduction (P = 0.015), and delayed reduction (P = 0.05) were found to statistically influence clinical results. We found that there were no injuries to the superior gluteal artery and nerve in spite of using a cable. Cerclage methods can be useful for initial reduction of displaced medial plates in acetabular fractures. These methods reduce operation time and blood loss as compared with other methods. PMID:23559194

Park, Myung-sik; Yoon, Sun Jung; Park, Jong-hyuk; Choi, Seung-min

2013-01-01

370

Successful obturator nerve repairing: Intraoperative sural nerve graft harvesting in endometrium cancer patient  

PubMed Central

INTRODUCTION Intraoperative injury of obturator nerve is a rare complication of gynecologic surgeries, it has been reported especially in patients with endometriosis and genitourinary malignancies. Gynecologic patients undergoing open lymphadenectomy are at increased risk of obturator nerve injury. PRESENTATION OF CASE A 60-year-old woman with FIGO stage II Grade II endometrial adenocarcinoma underwent bilateral pelvic paraaortic lymphadenectomy. During right obturator lymph node dissection, the right obturator nerve was inadvertently transected with Harmonic scalpel sealing system. The graft was used to anastomose epyneurium of distal segment of obturator nerve to its counterpart in the proximal segment with 10–0 prolen suture. DISCUSSION In case of iatrogenic nerve transection, microsurgical end to end tension-free coaptation is advocated. In case of the obturator nerve is fixed and because of the thermal injury end to end alignment can not be achieved, nerve grafting is necessary. CONCLUSION According to our knowledge, successful immediate grafting of iatrogenically damaged obturator nerve during pelvic lymphadenectomy in our patient is the third report of such a case, but also it has a unique feature of being the first obturator nerve repairing case after dissected with tissue sealing system which causes large sealed area that does not make it possible to make end-to-end anastomosis without nerve harvesting. PMID:24814984

Harma, Müge; Sel, Görker; Aç?kgöz, Bekta?; Harma, Mehmet ?brahim

2014-01-01

371

Corn root gravitropism  

NSDL National Science Digital Library

Gravitropism is the turning or growing in a different direction of a plant in response to gravity. This corn plant's root grows downward and exhibits positive gravitropism because it is growing toward gravity's pull.

Roger P. Hangarter (Indiana University;Department of Biology)

2000-01-01

372

Topics In Primitive Roots  

E-print Network

This note considers a few topics in the theory of primitive roots g(p) modulo a prime p>=2. A few estimates of the least primitive roots g(p) and the least prime primitive roots g^*(p) modulo p, a large prime, are determined. One of the estimate here seems to sharpen the Burgess estimate g(p) 0, to the smaller estimate g(p) 2. The expected order of magnitude is g(p) 1 constant. The corresponding estimates for least prime primitive roots g^*(p) are slightly higher. The last topic deals with an effective lower bound #{p > x/log x for the number of primes p 1. The current results in the literature claim the lower bound #{p > x/(log x)^2, and have restrictions on the minimal number of fixed integers to three or more.

N. A. Carella

2014-05-01

373

Evolution of nerve development in frogs. II. Modified development of the peripheral nervous system in the direct-developing frog Eleutherodactylus coqui (Leptodactylidae).  

PubMed

We use whole-mount immunohistochemistry to describe the pattern of development of cranial nerves and muscles in the direct-developing leptodactylid frog Eleutherodactylus coqui. Comparison with nerve development in the biphasically developing frogs Physalaemus pustulosus (Leptodactylidae) and Discoglossus pictus (Discoglossidae; described in a companion paper) allows us to infer the ancestral leptodactylid ontogenetic pattern and the extent to which it has been modified during the evolution of direct development in Eleutherodactylus. While early embryonic development of cranial nerves and muscles is remarkably conserved in E. coqui, most transitory embryonic and larval characters (e.g., occipital and spinal myotomes together with their innervation, the distorted course of trigeminal and facial nerves, ventral branchial arch muscles, a subset of branchial-nerve rami and the lateral-line system) never develop. However, a few larva-typical characters are recapitulated, including Rohon-Beard cells and an anastomosis between the vagal and hypoglossal nerve. In addition to the abbreviation of ontogeny by loss of larva-specific traits, dramatic dissociations and heterochronic shifts of characters can be observed in E. coqui. The onset of development of limb and trunk innervation has been pre-displaced to early embryonic stage. Moreover, the reorientation of cranial muscles and nerves corresponding to late metamorphic events in biphasically developing anurans occurs relatively much earlier and is less pronounced in E. coqui resulting in an extreme condensation of ontogeny. PMID:9261555

Schlosser, G; Roth, G

1997-01-01

374

Cotton Root-rot.  

E-print Network

excelsa, Pinus sylvestri.s, Strobw, P. Laricio, Larix Europoea, Acer platanoides. Fagus. This disease manifests itself by the blackening of the roots and rootlets. The Cotylcdons have a spotted appearance. Warm and moist weather causes the fungus... Persimmon (Diospyros Kaki) grafted on the native Per- simmon (D. Tri~~iniana), Silver Maple (Acer dasycarpum), Paper Mulberry (Broussonetia papyrifera). Of this list the China and Paper Mulberry trees suffer most. In August, 1888, the roots of a number...

Pammel, L. H. (Louis Herman)

1889-01-01

375

The catecholaminergic nerve plexus of Holothuroidea  

PubMed Central

Catecholamines have been extensively reported to be present in most animal groups, including members of Echinodermata. In this study, we investigated the presence and distribution of catecholaminergic nerves in two members of the Holothuroidea, Holothuria glaberrima (Selenka, 1867) (Aspidochirotida, Holothuroidea) and Holothuria mexicana (Ludwig, 1875) (Aspidochirotida, Holothuroidea), by using induced fluorescence for catecholamines on tissue sections and immunohistochemistry with an antibody that recognizes tyrosine hydroxylase. The presence of a catecholaminergic nerve plexus similar in distribution and extension to those previously reported in other members of Echinodermata was observed. This plexus, composed of cells and fibers, is found in the ectoneural component of the echinoderm nervous system and is continuous with the circumoral nerve ring and the radial nerves, tentacular nerves, and esophageal plexus. In addition, fluorescent nerves in the tube feet are continuous with the catecholaminergic components of the radial nerve cords. This is the first comprehensive report on the presence and distribution of catecholamines in the nervous system of Holothuroidea. The continuity and distribution of the catecholaminergic plexus strengthen the notion that the catecholaminergic cells are interneurons, since these do not form part of the known sensory or motor circuits and the fluorescence is confined to organized nervous tissue. PMID:20827375

Díaz-Balzac, Carlos A.; Mejías, Wigberto; Jiménez, Luis B.

2010-01-01

376

Posterior Interosseous Nerve Syndrome from Thermal Injury  

PubMed Central

Background. Due to anatomical proximity to bone, the radial nerve is the most frequently injured major nerve of the upper extremity, frequently secondary to fractures (Li et al. (2013)). We describe an incidence when a branch of the radial nerve is injured as a result of a thermal injury. Observation. Radial nerve injury can occur anywhere along the anatomical course with varied etiologies, but commonly related to trauma. The most frequent site is in the proximal forearm involving the posterior interosseous branch. However, problems can occur at the junction of the middle and proximal thirds of the humerus and wrist radially. When the radial nerve is injured by a burn, a new rehabilitation dynamic arises. Not only does one agonize about the return of nerve function but also fret about the skin grafts that replaced the devitalized tissue housing that compartment. Discussion. Although posterior interosseous nerve syndrome has been described in the context of many different etiologies, it has not previously been discussed in relation to burn injuries. In this case, not only did the patient's rehabilitation involve aggressive therapy for return of sensation and function of the arm, but also prevention of contracture normally seen in replacement of full thickness burns. PMID:24707432

Singh, Vijay A.; Michael, Rami E.; Dinh, Duy-Bao P.; Bloom, Scott; Cooper, Michael

2014-01-01

377

Nerve repair: toward a sutureless approach.  

PubMed

Peripheral nerve repair for complete section injuries employ reconstructive techniques that invariably require sutures in their application. Sutures are unable to seal the nerve, thus incapable of preventing leakage of important intraneural fluids from the regenerating nerve. Furthermore, sutures are technically demanding to apply for direct repairs and often induce detrimental scarring that impedes healing and functional recovery. To overcome these limitations, biocompatible and biodegradable glues have been used to seal and repair peripheral nerves. Although creating a sufficient seal, they can lack flexibility and present infection risks or cytotoxicity. Other adhesive biomaterials have recently emerged into practice that are usually based on proteins such as albumin and collagen or polysaccharides like chitosan. These adhesives form their union to nerve tissue by either photothermal (tissue welding) or photochemical (tissue bonding) activation with laser light. These biomaterial adhesives offer significant advantages over sutures, such as their capacity to unite and seal the epineurium, ease of application, reduced invasiveness and add the potential for drug delivery in situ to facilitate regeneration. This paper reviews a number of different peripheral nerve repair (or reconstructive) techniques currently used clinically and in experimental procedures for nerve injuries with or without tissue deficit. PMID:25015388

Barton, Matthew J; Morley, John W; Stoodley, Marcus A; Lauto, Antonio; Mahns, David A

2014-10-01

378

Roots and Extremal Points  

NASA Astrophysics Data System (ADS)

In computational physics very often roots and local extrema of a function have to be determined. In one dimension bisection is a very robust but rather inefficient root finding method. If a good starting point close to the root is available and the function is smooth enough, the Newton-Raphson method converges much faster. Special strategies are necessary to find roots of not so well behaved functions or higher order roots. The combination of bisection and interpolation as by the methods of Dekker, Brent and more recently Chandrupatla provides generally applicable algorithms. In multidimensions Quasi-Newton methods are a good choice. Whereas local extrema can be found as the roots of the gradient, at least in principle, direct optimization can be more efficient. In one dimension the ternary search method or Brent's more efficient golden section search method can be used. In multidimensions the class of direction set search methods is very popular which includes the methods of steepest descent and conjugate gradients, the Newton-Raphson method and, if calculation of the full Hessian matrix is too expensive, the Quasi-Newton methods.

Scherer, Philipp O. J.

379

Laser welding of rat's facial nerve.  

PubMed

The aim of this study is to compare regeneration of the severed nerves that were repaired by laser welding with those repaired by microsurgical suturing and evaluate the value in use of laser nerve welding in the head and neck area. In 12 rats the buccal branches of the facial nerves on the both sides were transected, and CO2 laser welding of the epineurium was performed on the right side and microsurgical suture technique was applied on the left side. In six rats Cholera Toxin B Subunit (CTb) was injected in the epineurium distal to the nerve anastomosis site at postoperative week 4. Another six rats were treated exactly in the same way in postoperative week 8. Six normal rats were used as controls. Intact facial nerve was observed after injection of CTb as well. Neurons of facial nuclei labeled positively by CTb were detected immunohistochemically, and the numbers were counted. CTb-positive neurons in the control group were 1311 +/- 258 (n = 6). CTb-positive neurons in the group (n = 6) with laser nerve welding were 1174 +/- 122 in postoperative week 4 and 1562 +/- 565 in postoperative week 8. CTb-positive neurons in the group (n = 6) with microsurgical suture were 1066 +/- 89 in postoperative week 4 and 1443 +/- 531 in postoperative week 8. CTb-positive neurons were seen significantly more in the group with laser welding than in the group with microsurgical suture in postoperative week (P = 0.028), but there was not much difference in postoperative week 8 (P = 0.463). None of 12 rats showed dehiscence at the nerve anastomosis done by laser welding. This study shows that nerve regeneration is more apparent in the nerve repaired by laser welding than in that repaired by microsurgical suture. PMID:16327562

Hwang, Kun; Kim, Sun Goo; Kim, Dae Joong; Lee, Chang Hyun

2005-11-01

380

Repair of peripheral nerve with vein wrapping*  

PubMed Central

Objective The post–traumatic neuro-anastomosis must be protected from the surrounding environment. This barrier must be biologically inert, biodegradable, not compressing but protecting the nerve. Formation of painful neuroma is one of the major issues with neuro-anastomosis; currently there is no consensus on post-repair neuroma prevention. Aim of this study is to evaluate the efficacy of neuroanastomosis performed with venous sheath to reduce painful neuromas formation, improve the electrical conductivity of the repaired nerve, and reduce the discrepancies of the sectioned nerve stumps. Patients and methods From a trauma population of 320 patients treated in a single centre between January 2008 and December 2011, twenty-six patients were identified as having an injury to at least one of the peripheral nerves of the arm and enrolled in the study. Patients were divided into two groups. In the group A (16 patients) the end-to-end nerve suture was wrapped in a vein sheath and compared with the group B (10 patients) in which a simple end-to-end neurorrhaphy was performed. The venous segment used to cover the nerve micro-suture was harvested from the superficial veins of the forearm. The parameters analyzed were: functional recovery of motor nerves, sensitivity and pain. Results Average follow-up was 14 months (range: 12–24 months). The group A showed a more rapid motor and sensory recovery and a reduction of the painful symptoms compared to the control group (B). Conclusions The Authors demonstrated that, in their experience, the venous sheath provides a valid solution to avoid the dispersion of the nerve fibres, to prevent adherent scars and painful neuromas formation. Moreover it can compensate the different size of two nerve stumps, allowing, thereby, a more rapid functional and sensitive recovery without expensive devices. PMID:24841688

LEUZZI, S.; ARMENIO, A.; LEONE, L.; DE SANTIS, V.; DI TURI, A.; ANNOSCIA, P.; BUFANO, L.; PASCONE, M.

2014-01-01

381

Study on Variant Anatomy of Sciatic Nerve  

PubMed Central

Introduction: Sciatic Nerve (SN) is the nerve of the posterior compartment of thigh formed in the pelvis from the ventral rami of the L4 to S3 spinal nerves. It leaves the pelvis via the greater sciatic foramen below piriformis and divides into Common Peroneal Nerve (CPN) and Tibial Nerve (TN) at the level of the upper angle of the popliteal fossa. Higher division of the sciatic nerve is the most common variation where the TN and CPN may leave the pelvis through different routes. Such variation may lead to compression of the nerve and lead to Non-discogenic sciatica. Materials and Methods: Fifty lower limbs were used for the study from Department of Anatomy, J.J.M.M.C Davangere, Karnataka, India. Observation and Results: In our study on 25 cadavers (50 lower limbs), we have observed 4 (8 %) lower limbs high division of sciatic nerve was noted. High division of sciatic nerve in the back of thigh was noted in one specimen (2%), while high division within the pelvis was noted in 3 specimens (6%), while in 46 (92%) it occurred outside the pelvis. Conclusion: Knowledge regarding such variation and differences in the course of SN is important for the surgeons to plan for various surgical interventions pertaining to the gluteal region. The variant anatomy of SN may cause piriformis syndrome and failure of SN block. Hence present study is undertaken to know the level of division, exit, course, relationship to piriformis and variations in the branching pattern of SN. PMID:25302181

V, Sangeetha

2014-01-01

382

Glomus Tumor in the Femoral Nerve  

PubMed Central

The glomus tumor of the peripheral nerve is one of the mesenchymal tumors originating in the epineurium, and is extremely rare. A 56-year-old man presented complaining of lancinating pain on the left thigh, which was provoked by pressure or exercise. Subsequent image study revealed a mass in the femoral nerve. Total surgical excision with the aid of intraoperative ultrasonography was performed and the pain was successfully controlled. The authors report an unusual case of a patient diagnosed with glomus tumor in peripheral nerve, with a review of the clinical features, imaging, and pathological findings. PMID:24527203

Park, Dong Sun; Chun, Young Il; Moon, Chang-Taek

2013-01-01

383

A new way to lose your nerve.  

PubMed

Peripheral nerve damage results in loss of sensation in the affected region of the body. Oaklander and Brown now report that, in the rat, transection of a peripheral nerve in only one side of the body also results in profound loss of the innervation of the same region on the opposite side of the body. Peripheral nerve damage may also produce persistent (neuropathic) pain conditions that are presumed to arise from maladaptive reorganization of the central nervous system. Thus, the possibility that comparable bilateral changes occur in patients and that such changes contribute to neuropathic pain conditions must be considered. PMID:15084736

Basbaum, Allan I

2004-04-14

384

Shrapnel injury of isolated third cranial nerve.  

PubMed

Isolated third nerve palsy develops in numerous intracranial pathologies such as closed head trauma, tumor, and aneurysm. Isolated oculomotor nerve palsy caused by shrapnel injury is uncommon. After a penetrating intracranial shrapnel injury, our patient with oculomotor ophthalmoplegia underwent surgery. Microsurgery removed the shrapnel that was applying pressure on the third nerve, resulting in contusion. A partial recovery associated with regeneration was observed at month 9. Extraocular muscle surgery should be planned if palsy does not resolve over a prolonged period of time. PMID:25485217

Uluta?, Murat; Seçer, Mehmet

2014-12-01

385

Wavelet denoising of displacement estimates in elastography.  

PubMed

Wavelet shrinkage denoising of the displacement estimates to reduce noise artefacts, especially at high overlaps in elastography, is presented in this paper. Correlated errors in the displacement estimates increase dramatically with an increase in the overlap between the data segments. These increased correlated errors (due to the increased correlation or similarity between consecutive displacement estimates) generate the so-called "worm" artefact in elastography. However, increases in overlap on the order of 90% or higher are essential to improve axial resolution in elastography. The use of wavelet denoising significantly reduces errors in the displacement estimates, thereby reducing the worm artefacts, without compromising on edge (high-frequency or detail) information in the elastogram. Wavelet denoising is a term used to characterize noise rejection by thresholding the wavelet coefficients. Worm artefacts can also be reduced using a low-pass filter; however, low-pass filtering of the displacement estimates does not preserve local information such as abrupt change in slopes, causing the smoothing of edges in the elastograms. Simulation results using the analytic 2-D model of a single inclusion phantom illustrate that wavelet denoising produces elastograms with the closest correspondence to the ideal mechanical strain image. Wavelet denoising applied to experimental data obtained from an in vitro thermal lesion phantom generated using radiofrequency (RF) ablation also illustrates the improvement in the elastogram noise characteristics. PMID:15121250

Techavipoo, Udomchai; Varghese, Tomy

2004-04-01

386

Conflict induced internal displacement in Nepal.  

PubMed

Nepal has witnessed a humanitarian crisis since the Maoist conflict began ten years ago. The plight of internally displaced persons (IDPs) in Nepal has received little international attention despite being rated one of the worst displacement scenarios in the world. An estimated 200,000 people have been displaced as a result of the conflict, with the far-western districts of Nepal being the worst affected. Internal displacement has stretched the carrying capacity of several cities with adverse physical and mental health consequences for the displaced. Vulnerable women and children have been the worst affected. The government has adopted a discriminatory approach and failed to fulfil its obligations towards IDPs. Non-governmental organisations and international agencies have provided inadequate services to IDPs in their programmes. Tackling the issues of IDPs requires co-operation between government and development agencies: acknowledging the burden of the problem of IDPs, adequate registration and needs assessment, along with health and nutritional surveys, and development of short-term emergency relief packages and long-term programmes for their assistance. PMID:17542185

Singh, Sonal; Sharma, Sharan Prakash; Mills, Edward; Poudel, Krishna C; Jimba, Masamine

2007-01-01

387

Ultra-Sensitive Magnetoresistive Displacement Sensing Device  

NASA Technical Reports Server (NTRS)

An ultrasensitive displacement sensing device for use in accelerometers, pressure gauges, temperature transducers, and the like, comprises a sputter deposited, multilayer, magnetoresistive field sensor with a variable electrical resistance based on an imposed magnetic field. The device detects displacement by sensing changes in the local magnetic field about the magnetoresistive field sensor caused by the displacement of a hard magnetic film on a movable microstructure. The microstructure, which may be a cantilever, membrane, bridge, or other microelement, moves under the influence of an acceleration a known displacement predicted by the configuration and materials selected, and the resulting change in the electrical resistance of the MR sensor can be used to calculate the displacement. Using a micromachining approach, very thin silicon and silicon nitride membranes are fabricated in one preferred embodiment by means of anisotropic etching of silicon wafers. Other approaches include reactive ion etching of silicon on insulator (SOI), or Low Pressure Chemical Vapor Deposition of silicon nitride films over silicon substrates. The device is found to be improved with the use of giant magnetoresistive elements to detect changes in the local magnetic field.

Olivas, John D. (Inventor); Lairson, Bruce M. (Inventor); Ramesham, Rajeshuni (Inventor)

2003-01-01

388

The Achyranthes bidentata polypeptide k fraction enhances neuronal growth in vitro and promotes peripheral nerve regeneration after crush injury in vivo  

PubMed Central

We have previously shown that Achyranthes bidentata polypeptides (ABPP), isolated from Achyranthes bidentata Blume (a medicinal herb), exhibit neurotrophic and neuroprotective effects on the nervous system. To identify the major active component of ABPP, and thus optimize the use of ABPP, we used reverse-phase high performance liquid chromatography to separate ABPP. We obtained 12 fractions, among which the fraction of ABPPk demonstrated the strongest neuroactivity. Immunocytochemistry and western blot analysis showed that ABPPk promoted neurite growth in cultured dorsal root ganglion explant and dorsal root ganglion neurons, which might be associated with activation of Erk1/2. A combination of behavioral tests, electrophysiological assessment, and histomorphometric analysis indicated that ABPPk enhanced nerve regeneration and function restoration in a mouse model of crushed sciatic nerve. All the results suggest that ABPPk, as the key component of ABPP, can be used for peripheral nerve repair to yield better outcomes than ABPP.

Cheng, Qiong; Jiang, Chunyi; Wang, Caiping; Yu, Shu; Zhang, Qi; Gu, Xiaosong; Ding, Fei

2014-01-01

389

Root architecture impacts on root decomposition rates in switchgrass  

NASA Astrophysics Data System (ADS)

Roots strongly contribute to soil organic carbon accrual, but the rate of soil carbon input via root litter decomposition is still uncertain. Root systems are built up of roots with a variety of different diameter size classes, ranging from very fine to very coarse roots. Since fine roots have low C:N ratios and coarse roots have high C:N ratios, root systems are heterogeneous in quality, spanning a range of different C:N ratios. Litter decomposition rates are generally well predicted by litter C:N ratios, thus decomposition of roots may be controlled by the relative abundance of fine versus coarse roots. With this study we asked how root architecture (i.e. the relative abundance of fine versus coarse roots) affects the decomposition of roots systems in the biofuels crop switchgrass (Panicum virgatum L.). To understand how root architecture affects root decomposition rates, we collected roots from eight switchgrass cultivars (Alamo, Kanlow, Carthage, Cave-in-Rock, Forestburg, Southlow, Sunburst, Blackwell), grown at FermiLab (IL), by taking 4.8-cm diameter soil cores from on top of the crown and directly next to the crown of individual plants. Roots were carefully excised from the cores by washing and analyzed for root diameter size class distribution using WinRhizo. Subsequently, root systems of each of the plants (4 replicates per cultivar) were separated in 'fine' (0-0.5 mm), 'medium' (0.5-1 mm) and 'coarse' roots (1-2.5 mm), dried, cut into 0.5 cm (medium and coarse roots) and 2 mm pieces (fine roots), and incubated for 90 days. For each of the cultivars we established five root-treatments: 20g of soil was amended with 0.2g of (1) fine roots, (2) medium roots, (3) coarse roots, (4) a 1:1:1 mixture of fine, medium and coarse roots, and (5) a mixture combining fine, medium and coarse roots in realistic proportions. We measured CO2 respiration at days 1, 3, 7, 15, 30, 60 and 90 during the experiment. The 13C signature of the soil was -26‰, and the 13C signature of plants was -12‰, enabling us to differentiate between root-derived C and native SOM-C respiration. We found that the relative abundance of fine, medium and coarse roots were significantly different among cultivars. Root systems of Alamo, Kanlow and Cave-in-Rock were characterized by a large abundance of coarse-, relative to fine roots, whereas Carthage, Forestburg and Blackwell had a large abundance of fine, relative to coarse roots. Fine roots had a 28% lower C:N ratio than medium and coarse roots. These differences led to different root decomposition rates. We conclude that root architecture should be taken into account when predicting root decomposition rates; enhanced understanding of the mechanisms of root decomposition will improve model predictions of C input to soil organic matter.

de Graaff, M.; Schadt, C.; Garten, C. T.; Jastrow, J. D.; Phillips, J.; Wullschleger, S. D.

2010-12-01

390

Expanded polytetrafluoroethylene entubulation of the rabbit inferior alveolar nerve  

Microsoft Academic Search

Objective. The purpose of this study was to evaluate the use of an expanded polytetrafluoroethylene conduit in the treatment of a 6.0-mm gap in the rabbit inferior alveolar nerve and compare the results with those of an autogenous interpositional tibial nerve graft. Study design. The inferior alveolar nerves of 5 adult New Zealand White female rabbits (10 nerves) were exposed

Michael Miloro; Jacqueline M. Macy

2000-01-01

391

Nerve excitability properties in early preclinical diabetic neuropathy  

Microsoft Academic Search

Diabetic polyneuropathy can be easily diagnosed when the nerve conduction studies are affected. Strength Duration Time (SDTc) reflects nerve excitability properties and was previously used several times to demonstrate the excitability properties of the nerves in the existence of electrophysiologically developed diabetic polyneuropathy. But as we all know, diabetic patients may experience neuropathic symptoms even though their routine nerve conduction

Ça?da? Erdo?an; Mehmet Yücel; Eylem De?irmenci; O?uzhan Öz; Hakan Akgün; Zeki Odaba??

2011-01-01

392

Triptolide improves nerve regeneration and functional recovery following crush injury to rat sciatic nerve.  

PubMed

Recently, accumulating data have demonstrated that triptolide exhibits neurotrophic and neuroprotective properties. However, the role of triptolide in repair and regeneration of peripheral nerve injury (PNI) has rarely been performed. The current study was designed to observe the possible beneficial effect of triptolide on promoting peripheral nerve regeneration in rats. Rats with sciatic nerve crush injury were administered daily with triptolide for 7 days. Axonal regeneration was evaluated by morphometric analysis and Fluoro-gold retrograde tracing. Motor functional recovery was evaluated by walking track analysis, electrophysiological assessment and histological appearance of target muscles. Levels of pro-inflammatory cytokines within injured nerves were also determined. The results demonstrated that triptolide was capable of promoting peripheral nerve regeneration. Additionally, triptolide significantly decreased the levels of pro-inflammatory cytokines within injured nerves. These findings indicate the possibility of developing triptolide as a therapeutic agent for PNI. The neuroprotective effects of triptolide might be associated with its anti-inflammatory properties. PMID:24406146

Zhang, Yong-Guang; Sheng, Qing-Song; Wang, Hong-Kun; Lv, Li; Zhang, Jun; Chen, Jian-Mei; Xu, Hao

2014-02-21

393

Early nodulines in root development  

Microsoft Academic Search

The symbiotic interaction between bacteria of the genus Rhizobium and leguminous plants leads to the formation of root nodules, which are specific nitrogen-fixing organs on the roots of plants. Bacteria enter the root by infection threads, and concomitantly cell divisons are induced in the root cortex, which lead to the formation of a meristern. From this meristern the different tissues

B. Scheres

1990-01-01

394

Developmental Changes in Peanut Root Structure during Root Growth and Root-structure Modification by Nodulation  

PubMed Central

Background and Aims Basic information about the root and root nodule structure of leguminous crop plants is incomplete, with many aspects remaining unresolved. Peanut (Arachis hypogaea) forms root nodules in a unique process. Structures of various peanut root types were studied with emphasis on insufficiently characterized lateral roots, changes in roots during their ontogenesis and root modification by nodule formation. Methods Peanut plants were grown in the field, in vermiculite or in filter paper. The taproot, first-order and second-order lateral roots and root nodules were analysed using bright-field and fluorescence microscopy with hand sections and resin sections. Key Results Three root categories were recognized. The primary seminal root was thick, exhibiting early and intensive secondary thickening mainly on its base. It was tetrarch and contained broad pith. First-order lateral roots were long and thin, with limited secondary thickening; they contained no pith. Particularly different were second- and higher-order lateral roots, which were anatomically simple and thin, with little or no secondary growth. Unusual wall ingrowths were visible in the cells of the central part of the cortex in the first-order and second-order lateral roots. The nodule body was formed at the junction of the primary and lateral roots by the activity of proliferating cells derived originally from the pericycle. Conclusions Two morphologically and anatomically distinct types of lateral roots were recognized: long, first-order lateral roots, forming the skeleton of the root system, and thin and short second- and higher-order lateral roots, with an incomplete second state of endodermal development, which might be classified as peanut ‘feeder roots’. Formation of root nodules at the base of the lateral roots was the result of proliferating cell divisions derived originally from the pericycle. PMID:18256023

Tajima, Ryosuke; Abe, Jun; Lee, O. New; Morita, Shigenori; Lux, Alexander

2008-01-01

395

Iridovirus in the root weevil Diaprepes abbreviatus.  

PubMed

Invertebrate iridescent virus 6 (IIV6) was evaluated for mode of transmission and ability to cause infection in the root weevil, Diaprepes abbreviatus (L.). This is the first evidence of IIV6 infection in D. abbreviatus, which caused both patent and sub-lethal covert infections in both larvae and adults. Adults and larvae were successfully infected with IIV6 by puncture, injection and per os. Transmission of IIV6 was demonstrated between infected and healthy individuals regardless of gender. Virus was detected in egg masses produced by virus-infected females suggesting IIV6 is transmitted transovarially. Virus particles were observed in the cytoplasm of weevil cells, and were shown to infect fat bodies, muscle, and nerve tissues, as visualized using transmission electron microscopy. Patent infections resulted in death of individuals within 3 to 4 days post infection. Individuals with covert infections tested positive for virus infection on day 7 by polymerase chain reaction analysis. Sequencing of PCR amplicons confirmed virus infection. Discovery of new pathogens against root weevils may provide new management tools for development of control strategies based on induced epizootics. This is the first report of a virus infecting D. abbreviatus. PMID:15841225

Hunter, W B; Lapointe, S L; Sinisterra, X H; Achor, D S; Funk, C J

2003-01-01

396

Clinical outcomes for Conduits and Scaffolds in peripheral nerve repair  

PubMed Central

The gold standard of peripheral nerve repair is nerve autograft when tensionless repair is not possible. Use of nerve autograft has several shortcomings, however. These include limited availability of donor tissue, sacrifice of a functional nerve, and possible neuroma formation. In order to address these deficiencies, researchers have developed a variety of biomaterials available for repair of peripheral nerve gaps. We review the clinical studies published in the English literature detailing outcomes and reconstructive options. Regardless of the material used or the type of nerve repaired, outcomes are generally similar to nerve autograft in gaps less than 3 cm. New biomaterials currently under preclinical evaluation may provide improvements in outcomes.

Gerth, David J; Tashiro, Jun; Thaller, Seth R

2015-01-01

397

Clinical outcomes for Conduits and Scaffolds in peripheral nerve repair.  

PubMed

The gold standard of peripheral nerve repair is nerve autograft when tensionless repair is not possible. Use of nerve autograft has several shortcomings, however. These include limited availability of donor tissue, sacrifice of a functional nerve, and possible neuroma formation. In order to address these deficiencies, researchers have developed a variety of biomaterials available for repair of peripheral nerve gaps. We review the clinical studies published in the English literature detailing outcomes and reconstructive options. Regardless of the material used or the type of nerve repaired, outcomes are generally similar to nerve autograft in gaps less than 3 cm. New biomaterials currently under preclinical evaluation may provide improvements in outcomes. PMID:25685760

Gerth, David J; Tashiro, Jun; Thaller, Seth R

2015-02-16

398

Intraoperative Facial Nerve Monitoring (IFNM) Predicts Facial Nerve Outcome after Resection of Vestibular Schwannoma  

Microsoft Academic Search

Summary   Intraoperative facial nerve monitoring (IFNM) is a suitable technique for intraoperative facial nerve identification and\\u000a dissection, especially in large vestibular schwannomas (VS) (acoustic neuroma). To evaluate its feasibility for estimating\\u000a functional nerve outcome after VS resection 60 patients underwent surgery using IFNM. Out of this group the last 40 patients\\u000a were included in a prospective study evaluating the prognostic

S. B. Sobottka; G. Schackert; S. A. May; M. Wiegleb; G. Reiß

1998-01-01

399

HELIUM EFFECTS ON DISPLACEMENT CASCADE IN TUNGSTEN  

SciTech Connect

Molecular dynamics (MD) simulations were performed to investigate He effects on displacement cascades in W. Helium content, proportion of interstitial and substitutional He and temperature were varied to reveal the various effects. The effect of interstitial He on the number of self-interstitial atoms (SIAs) produced during cascade damage appears to be insignificant. However, interstitial He tends to fill a vacancy (V). Nevertheless, this process is less favorable than SIA-V recombination particularly when excess SIAs are present before a cascade. The efficiency of He filling and SIA-V recombination increases as temperature increases due to increased point defect mobility. Likewise, substitutional He is more susceptible to displacement during a collision cascade than W. This susceptibility increases towards higher temperatures. Consequently, the number of surviving V is governed by the interplay between displaced substitutional He and SIA-V recombination. The temperature dependence of these processes results in a minimum number of V reached at an intermediate temperature.

Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

2013-09-30

400

Frictional behavior of large displacement experimental faults  

USGS Publications Warehouse

The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity dependence of dilatancy rate of simulated gouge fails to quantitatively account for the experimental observations.

Beeler, N.M.; Tullis, T.E.; Blanpied, M.L.; Weeks, J.D.

1996-01-01

401

Treatment of peroneal nerve injuries with simultaneous tendon transfer and nerve exploration  

PubMed Central

Background Common peroneal nerve palsy leading to foot drop is difficult to manage and has historically been treated with extended bracing with expectant waiting for return of nerve function. Peroneal nerve exploration has traditionally been avoided except in cases of known traumatic or iatrogenic injury, with tendon transfers being performed in a delayed fashion after exhausting conservative treatment. We present a new strategy for management of foot drop with nerve exploration and concomitant tendon transfer. Method We retrospectively reviewed a series of 12 patients with peroneal nerve palsies that were treated with tendon transfer from 2005 to 2011. Of these patients, seven were treated with simultaneous peroneal nerve exploration and repair at the time of tendon transfer. Results Patients with both nerve repair and tendon transfer had superior functional results with active dorsiflexion in all patients, compared to dorsiflexion in 40% of patients treated with tendon transfers alone. Additionally, 57% of patients treated with nerve repair and tendon transfer were able to achieve enough function to return to running, compared to 20% in patients with tendon transfer alone. No patient had full return of native motor function resulting in excessive dorsiflexion strength. Conclusion The results of our limited case series for this rare condition indicate that simultaneous nerve repair and tendon transfer showed no detrimental results and may provide improved function over tendon transfer alone. PMID:25099247

2014-01-01

402

Low intensity laser treatment of nerve injuries  

NASA Astrophysics Data System (ADS)

The neural regeneration and functional recovery after nerve injuries has long been an important field in neuroscience. Low intensity laser (LIL) irradiation is a novel and useful tool for the treatment of many injuries and disorders. The aim of this study was to assess the role of LIL irradiation in the treatment of peripheral and central nerve injuries. Some animal experiments and clinical investigations have shown beneficial effects of LIL irradiation on neural tissues, but its therapeutic value and efficacy are controversial. Reviewing the data of experimental and clinical studies by using the biological information model of photobiomodulation, we conclude that LIL irradiation in specific parameters can promote the regeneration of injured peripheral and central nerves and LIL therapy is a safe and valuable treatment for superficial peripheral nerve injuries and spinal cord injury. The biological effects of LIL treatment depend largely on laser wavelength, power and dose per site and effective irradiation doses are location-specific.

Liu, Xiao-Guang; Liu, Timon Cheng-Yi; Luo, Qing-Ming

2007-05-01

403

Electrical stimulation for promoting peripheral nerve regeneration.  

PubMed

The peripheral nervous system has the intrinsic capacity to regenerate axons into target tissues, and peripheral nerves severely damaged or transected can be reconstructed by microsurgical techniques. The aim of peripheral nerve surgery is to pave way for fast and most possible thorough functional recovery. However, full functional recovery is rarely seen and several reasons for this have already been discovered. Based on these discoveries, therapeutic strategies supplementary to nerve microsurgery have been conceived with electrical stimulation of the denervated muscles or the proximal nerve stump or reconstructed area itself being among them. This chapter shortly describes the commonly accepted reasons for incomplete functional recovery and reviews the effects of varying electrical stimulation paradigms on the essentials for axonal regeneration and functional target reinnervation. We conclude the chapter with promising examples where electrical stimulation did already demonstrate to accelerate and increase functional recovery in the clinic. PMID:24093609

Haastert-Talini, Kirsten; Grothe, Claudia

2013-01-01

404

Peripheral nerve ultrasound in ALS phenotypes.  

PubMed

Introduction. We sought to determine the cross sectional area (CSA) of peripheral nerves in patients with distinct subtypes of amyotrophic lateral sclerosis (ALS). Methods. Ulnar and median nerve ultrasound was performed in 78 ALS patients [classic, n=21, upper motor neuron dominant (UMND), n=14, lower motor neuron dominant (LMND), n=20, bulbar, n=15, primary lateral sclerosis (PLS) n=8] and 18 matched healthy controls. Results. Compared to controls ALS patients had significant, distally pronounced reductions of ulnar CSA (forearm/wrist level) across all disease groups except for PLS. Median nerve CSA (forearm/wrist level) did not differ between controls and ALS. Conclusion. Ulnar nerve ultrasound in ALS subgroups revealed significant differences in distal CSA values, which suggests it has value as a marker of LMN involvement. Its potential was particularly evident in UMND and PLS groups, which can be hard to separate clinically, yet their accurate separation has important prognostic implications. © 2014 Wiley Periodicals, Inc. PMID:25155020

Schreiber, Stefanie; Abdulla, Susanne; Debska-Vielhaber, Grazyna; Machts, Judith; Dannhardt-Stieger, Verena; Feistner, Helmut; Oldag, Andreas; Goertler, Michael; Petri, Susanne; Kollewe, Katja; Kropf, Siegfried; Schreiber, Frank; Heinze, Hans-Jochen; Dengler, Reinhard; Nestor, Peter J; Vielhaber, Stefan

2014-08-25

405

Stem cells to replace the optic nerve  

Microsoft Academic Search

Methods that exist now and that might be developed are suggested to replace retinal ganglion cells and their axons in the optic nerve, ultimately to re-establish functional vision in eyes blind from glaucoma.

H A Quigley; D S Iglesia; HA Quigley

2004-01-01

406

Investigation of nerve injury through microfluidic devices  

PubMed Central

Traumatic injuries, both in the central nervous system (CNS) and peripheral nervous system (PNS), can potentially lead to irreversible damage resulting in permanent loss of function. Investigating the complex dynamics involved in these processes may elucidate the biological mechanisms of both nerve degeneration and regeneration, and may potentially lead to the development of new therapies for recovery. A scientific overview on the biological foundations of nerve injury is presented. Differences between nerve regeneration in the central and PNS are discussed. Advances in microtechnology over the past several years have led to the development of invaluable tools that now facilitate investigation of neurobiology at the cellular scale. Microfluidic devices are explored as a means to study nerve injury at the necessary simplification of the cellular level, including those devices aimed at both chemical and physical injury, as well as those that recreate the post-injury environment. PMID:24227311

Siddique, Rezina; Thakor, Nitish

2014-01-01

407

Rhetorics of Displacement: Constructing Identities in Forced Relocations  

ERIC Educational Resources Information Center

Forced displacement has often involved the use of rhetoric, both by government institutions and by people who struggle not only to survive displacement, but also to resist it. In this article, the author offers first a theoretical framework that informs her thinking about displacement narratives. She briefly examines two published displacement…

Powell, Katrina M.

2012-01-01

408

The optic nerve pathology in magnetic resonance imaging.  

PubMed

Magnetic resonance imaging (MRI) delineates the orbital soft tissue excellently and is a valuable diagnostic tool in optic nerve pathology. By using different imaging parameters some examples are shown of demarcation of optic nerve tumors, optic nerve inflammations and orbital diseases surrounding the optic nerve. Whereas CT appears to be superior to MRI only in the detection of calcified perioptic meningiomas, MRI provides unique visualization of optic canal and even subarachnoidal space of retrobulbar optic nerve in peculiar cases. PMID:2079907

Wiegand, W

1990-01-01

409

Lipomatosis of the sciatic nerve: typical and atypical MRI features  

Microsoft Academic Search

Lipomatosis of nerve, also known as fibrolipomatous hamartoma, is a rare condition of nerve, usually affecting the median\\u000a nerve. The MRI appearance is characteristic. We describe two cases of lipomatosis of nerve involving the sciatic nerve, an\\u000a extremely unusual location for this lesion, in patients with sciatic neuropathy. These cases share the typical features previously\\u000a described in the literature for

Bernadette Zhi Ying Wong; Kimberly K. Amrami; Doris E. Wenger; P. James B. Dyck; Bernd W. Scheithauer; Robert J. Spinner

2006-01-01

410

Multiple cranial nerve dysfunction caused by neurosarcoidosis.  

PubMed

Neurosarcoidosis is a rare identity and occurs in only 5% to 15% of patients with sarcoidosis. It can manifest in many different ways, and therefore, diagnosis may be complicated. We report a case presented in a very unusual manner with involvement of 3 cranial nerves; anosmia (NI), facial palsy (NVII), and hearing loss (NVIII). When cranial nerve dysfunction occurs, it is very important to take neurosarcoidosis into consideration. PMID:22154016

Loor, Rivkah G J; van Tongeren, Joost; Derks, Wynia

2012-01-01

411

Macrodactyly-Lipofibromatous Hamartoma of Nerves  

Microsoft Academic Search

\\u000a Lipofibromatous hamartoma of nerve (LFHN) is a very uncommon benign lipomatous tumor with specific clinicopathological characteristics which may present with\\u000a or without macrodactyly. This tumor-like lesion is composed of fibrous and fatty tissues arising from the epi- and perineurium\\u000a that surrounds and infiltrates the major nerves and their branches in the body (Enzinger and Weiss 1994). It is believed to

Carola Duràn-Mckinster; Luz Orozco-Covarrubias; Marimar Saez-De-Ocariz; Ramòn Ruiz-Maldonado

412

Endoscopically assisted sural nerve harvest in infants.  

PubMed

A technique of endoscopic sural nerve harvest was devised to minimize the donor site scarring in infants requiring peripheral nerve grafting procedures. The harvests were performed under tourniquet control using three 2-cm incisions for access at the lateral malleolus, midcalf, and popliteal fossa. Endoscopic visualization and blunt dissection of the nerve was achieved with a 4-mm-diameter, 18-cm-long telescope with a 0-degree angle lens, stabilized in an Emory retractor and attached to a video camera. The medial sural nerve was divided in the popliteal fossa proximally under direct vision. The lateral sural nerve was identified and harvested when present. This technique has been in use since 1994 and has been undertaken in more than 200 patients. The most common indication for surgery was obstetrical brachial plexus palsy. No nerve graft injury was noted upon examination under the operating microscope. Postoperative pain, swelling, and ecchymosis were minimal. Most patients have a detectable area of sensory loss at long-term follow-up but are unaware of this finding. Donor site scarring has been aesthetically satisfactory. PMID:20567685

Capek, Lucie; Clarke, Howard M

2008-02-01

413

Upregulation of Bradykinin B2 Receptor Expression by Neurotrophic Factors and Nerve Injury in Mouse Sensory Neurons  

Microsoft Academic Search

Bradykinin B2 receptor mRNA was detected at low levels, both by RT-PCR and by in situ hybridization, in freshly isolated dorsal root ganglia (DRG) and in ganglia cultured in the absence of neurotrophic factors, but was strongly upregulated by culture in the presence of nerve growth factor (NGF). The effect of NGF is mediated via TrkA receptors. The related neurotrophins,

Yih-Jing Lee; Olof Zachrisson; David A. Tonge; Peter A. McNaughton

2002-01-01

414

Displaced retinal ganglion cells in albino and pigmented rats  

PubMed Central

We have studied in parallel the population of displaced retinal ganglion cells (dRGCs) and normally placed (orthotopic RGCs, oRGCs) in albino and pigmented rats. Using retrograde tracing from the optic nerve, from both superior colliculi (SC) or from the ipsilateral SC in conjunction with Brn3 and melanopsin immunodetection, we report for the first time their total number and topography as well as the number and distribution of those dRGCs and oRGCs that project ipsi- or contralaterally and/or that express any of the three Brn3 isoforms or melanopsin. The total number of RGCs (oRGCs+dRGCs) is 84,706 ± 1249 in albino and 90,440 ± 2236 in pigmented, out of which 2383 and 2428 are melanopsin positive (m-RGCs), respectively. Regarding dRGCs: i/ albino rats have a significantly lower number of dRGCs than pigmented animals (0.5% of the total number of RGCs vs. 2.5%, respectively), ii/ dRGCs project massively to the contralateral SC, iii/ the percentage of ipsilaterality is higher for dRGCs than for oRGCs, iv/ a higher proportion of ipsilateral dRGCs is observed in albino than pigmented animals, v/ dRGC topography is very specific, they predominate in the equatorial temporal retina, being densest where the oRGCs are densest, vi/ Brn3a detects all dRGCs except half of the ipsilateral ones and those that express melanopsin, vii/ the proportion of dRGCs that express Brn3b or Brn3c is slightly lower than in the oRGC population, viii/ a higher percentage of dRGCs (13% albino, 9% pigmented) than oRGCs (2.6%) express melanopsin, ix/ few m-RGCs (displaced and orthotopic) project to the ipsilateral SC, x/ the topography of m-dRGCs does not resemble the general distribution of dRGCs, xi/ The soma size in m-oRGCs ranges from 10 to 21 ?m and in m-dRGCs from 8 to 15 ?m, xii/ oRGCs and dRGCs have the same susceptibility to axonal injury and ocular hypertension. Although the role of mammalian dRGCs remains to be determined, our data suggest that they are not misplaced by an ontogenic mistake. PMID:25339868

Nadal-Nicolás, Francisco M.; Salinas-Navarro, Manuel; Jiménez-López, Manuel; Sobrado-Calvo, Paloma; Villegas-Pérez, María P.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

2014-01-01

415

Plasma extravasation in the skin and pelvic organs evoked by antidromic stimulation of the lumbosacral dorsal roots of the rat  

Microsoft Academic Search

Electrical stimulation of the distal stump of cut peripheral nerves is a commonly accepted way to evoke neurogenic inflammation. Nevertheless, the modulatory effect of biogenic amines and vasoactive peptides released from efferent fibres can be excluded only if the dorsal roots are stimulated. The present study was focussed to investigate plasma extravasation in the appropriate skin and mucosal areas as

E. Pintér; J. Szolcsányi

1995-01-01

416

Wired to the roots  

PubMed Central

Often, plant-pathogenic microbe interactions are discussed in a host-microbe two-component system, however very little is known about how the diversity of rhizospheric microbes that associate with plants affect host performance against pathogens. There are various studies, which specially direct the importance of induced systemic defense (ISR) response in plants interacting with beneficial rhizobacteria, yet we don’t know how rhizobacterial associations modulate plant physiology. In here, we highlight the many dimensions within which plant roots associate with beneficial microbes by regulating aboveground physiology. We review approaches to study the causes and consequences of plant root association with beneficial microbes on aboveground plant-pathogen interactions. The review provides the foundations for future investigations into the impact of the root beneficial microbial associations on plant performance and innate defense responses. PMID:23073006

Kumar, Amutha Sampath; Bais, Harsh P.

2012-01-01

417

[Iatrogenic injury of peripheral nerves].  

PubMed

Abstract There are many risks of iatrogenic peripheral-nerve injuries during routine medical procedures. These injuries may occur during venipuncture for drawing blood, endoscopic treatments, punctures of joints or ganglions, various kinds of surgical procedures, and in numerous other situations. It is important to create a "Manual" of such accidents or incidents. In case an accident occurs, both the medical staff and the injured patient should receive adequate support to avoid any anxiety. The doctor must examine the person's injury carefully, and must judge its severity as soon as possible. The doctor must also offer the patient a prompt explanation about their injury and its proper care or treatment. This explanation must be easy to understand. This step can reduce patient anxiety and even prevent the early stages of complex regional pain syndrome (CRPS). One of my therapeutic strategies for treating early-stage CRPS is to use prednisolone for a short period for the treatment of strong pain and serious edema; the other approach is to do administer a warm-cold alternating bath with range-of-motion (ROM) exercise. Creation of manuals and education of staff to quickly respond to such situations is extremely essential. PMID:25475033

Horiuchi, Yukio

2014-12-01

418

Vimentin regulates peripheral nerve myelination.  

PubMed

Myelination is a complex process that requires coordinated Schwann cell-axon interactions during development and regeneration. Positive and negative regulators of myelination have been recently described, and can belong either to Schwann cells or neurons. Vimentin is a fibrous component present in both Schwann cell and neuron cytoskeleton, the expression of which is timely and spatially regulated during development and regeneration. We now report that vimentin negatively regulates myelination, as loss of vimentin results in peripheral nerve hypermyelination, owing to increased myelin thickness in vivo, in transgenic mice and in vitro in a myelinating co-culture system. We also show that this is due to a neuron-autonomous increase in the levels of axonal neuregulin 1 (NRG1) type III. Accordingly, genetic reduction of NRG1 type III in vimentin-null mice rescues hypermyelination. Finally, we demonstrate that vimentin acts synergistically with TACE, a negative regulator of NRG1 type III activity, as shown by hypermyelination of double Vim/Tace heterozygous mice. Our results reveal a novel role for the intermediate filament vimentin in myelination, and indicate vimentin as a regulator of NRG1 type III function. PMID:22357929

Triolo, Daniela; Dina, Giorgia; Taveggia, Carla; Vaccari, Ilaria; Porrello, Emanuela; Rivellini, Cristina; Domi, Teuta; La Marca, Rosa; Cerri, Federica; Bolino, Alessandra; Quattrini, Angelo; Previtali, Stefano Carlo

2012-04-01

419

Malignant Peripheral Nerve Sheath Tumors  

PubMed Central

Malignant peripheral nerve sheath tumors (MPNST) are uncommon, biologically aggressive soft tissue sarcomas of neural origin that pose tremendous challenges to effective therapy. In 50% of cases, they occur in the context of neurofibromatosis type I, characterized by loss of function mutations to the tumor suppressor neurofibromin; the remainder arise sporadically or following radiation therapy. Prognosis is generally poor, with high rates of relapse following multimodality therapy in early disease, low response rates to cytotoxic chemotherapy in advanced disease, and propensity for rapid disease progression and high mortality. The last few years have seen an explosion in data surrounding the potential molecular drivers and targets for therapy above and beyond neurofibromin loss. These data span multiple nodes at various levels of cellular control, including major signal transduction pathways, angiogenesis, apoptosis, mitosis, and epigenetics. These include classical cancer-driving genetic aberrations such as TP53 and phosphatase and tensin homolog (PTEN) loss of function, and upregulation of mitogen-activated protein kinase (MAPK) and (mechanistic) target of rapamycin (TOR) pathways, as well as less ubiquitous molecular abnormalities involving inhibitors of apoptosis proteins, aurora kinases, and the Wingless/int (Wnt) signaling pathway. We review the current understanding of MPNST biology, current best practices of management, and recent research developments in this disease, with a view to informing future advancements in patient care. PMID:24470531

Farid, Mohamad; Demicco, Elizabeth G.; Garcia, Roberto; Ahn, Linda; Merola, Pamela R.; Cioffi, Angela

2014-01-01

420

Heavy metal displacement in chelate-irrigated soil during phytoremediation  

NASA Astrophysics Data System (ADS)

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

2003-03-01

421

The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks  

PubMed Central

Visible and invisible displacement tasks have been used widely for comparative studies of animals’ understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and thus reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so due to their inability to form a mental representation of the target object, or simply due to the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object’s location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species’ performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past. PMID:24611641

Müller, Corsin A.; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

2014-01-01

422

Effect of Delayed Peripheral Nerve Repair on Nerve Regeneration, Schwann Cell Function and Target Muscle Recovery  

PubMed Central

Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2–3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months. PMID:23409189

Jonsson, Samuel; Wiberg, Rebecca; McGrath, Aleksandra M.; Novikov, Lev N.; Wiberg, Mikael; Novikova, Liudmila N.; Kingham, Paul J.

2013-01-01

423

Borehole tool outrigger arm displacement control mechanism  

Microsoft Academic Search

As the outrigger arms of a borehole logging tool are flexed inwardly and outwardly according to the diameter of the borehole opening through which they pass, the corresponding axial displacements of the ends of the arms are controlled to determine the axial positions of the arms relative to the tool. Specifically, as the arm ends move, they are caused to

1985-01-01

424

REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES  

Microsoft Academic Search

Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES By Tung Minh Tran May 2002 Chairman: Dr Carl D Crane III Major Department: Mechanical Engineering A new type of parallel mechanism is introduced that is based on

TUNG MINH TRAN

425

Displacement Damage in Bipolar Linear Integrated Circuits  

NASA Technical Reports Server (NTRS)

Although many different processes can be used to manufacture linear integrated circuits, the process that is used for most circuits is optimized for high voltage -- a total power supply voltage of about 40 V -- and low cost. This process, which has changed little during the last twenty years, uses lateral and substrate p-n-p transistors. These p-n-p transistors have very wide base regions, increasing their sensitivity to displacement damage from electrons and protons. Although displacement damage effects can be easily treated for individual transistors, the net effect on linear circuits can be far more complex because circuit operation often depends on the interaction of several internal transistors. Note also that some circuits are made with more advanced processes with much narrower base widths. Devices fabricated with these newer processes are not expected to be significantly affected by displacement damage for proton fluences below 1 x 10(exp 12) p/sq cm. This paper discusses displacement damage in linear integrated circuits with more complex failure modes than those exhibited by simpler devices, such as the LM111 comparator, where the dominant response mode is gain degradation of the input transistor. Some circuits fail catastrophically at much lower equivalent total dose levels compared to tests with gamma rays. The device works satisfactorily up to nearly 1 Mrad(Si) when it is irradiated with gamma rays, but fails catastrophically between 50 and 70 krad(Si) when it is irradiated with protons.

Rax, B. G.; Johnston, A. H.; Miyahira, T.

2000-01-01

426

Ground Displacement by Strike-Slip Motion  

NSDL National Science Digital Library

This photograph illustrates strike-slip motion along a fault trace. The section of fence in the foreground has been offset 8.5 feet to the left relative to the segment in the background. The displacement occured in a rural area near Woodville, California, as a result of the San Francisco Earthquake on April 18, 1906.

427

Job Displacement and the Rural Worker.  

ERIC Educational Resources Information Center

High rates of unemployment in rural areas poses questions as what education can do with the problem. This report examines the effects of rural American economies as they grow away from agriculture and toward dependence on manufacturing and service industries. Using data from the federal Bureau of Labor Statistics' Displaced Worker Survey, the…

Podgursky, Michael

428

Ko Displacement Theory for Structural Shape Predictions  

NASA Technical Reports Server (NTRS)

The development of the Ko displacement theory for predictions of structure deformed shapes was motivated in 2003 by the Helios flying wing, which had a 247-ft (75-m) wing span with wingtip deflections reaching 40 ft (12 m). The Helios flying wing failed in midair in June 2003, creating the need to develop new technology to predict in-flight deformed shapes of unmanned aircraft wings for visual display before the ground-based pilots. Any types of strain sensors installed on a structure can only sense the surface strains, but are incapable to sense the overall def